The right shoes and rain jacket will shield you from the elements, but Merino wool clothing will keep you warm and comfortable no matter the conditions. We're going compare Icebreaker vs Smartwool to find out who makes the best Merino socks, shirts and more.
Whether you like hiking through forests or climbing rugged hills, you need great clothing to match your footwear.
Merino wool is one of the highest quality materials available, for a variety of reasons.
But with so many brands to choose from, where do you start?
You can begin by comparing a couple first like we've done here with Icebreaker vs Smartwool.
These two brands offer high-quality products, with decent prices to match.
Icebreaker vs Smartwool Comparison
|Product Name||Icebreaker Hike+ Light Crew Sock||Smartwool Hike Light Crew Socks|
|Material||59% Merino Wool, 38% Nylon, 3% LYCRA®||69% Merino Wool, 30% Nylon, 1% Elastane|
|Fit (hight, anatomic)||crew/mid-calf, left/right anatomic fit||crew/mid-calf|
|Best For||hike, adventure,outdoors, casual||hike, walk, outdoors, casual|
|Warranty||lifetime||2 years satisfaction guarantee|
|See Price on Amazon||Men's Women's||Men's Women's|
|Product Name||Icebreaker Tech Lite Short Sleeve Crewe||Smartwool Merino 150 Baselayer Short Sleeve|
|Material||87% Merino Wool, 13% Nylon corespun||87% Merino Wool, 13% Nylon Core|
|Weight||150 Ultralight||150 smartwool's lightest|
|Best For||lifestyle, traveling, skiing, hiking, casual||lifestyle, biking, hiking, traveling, casual|
|See Price on Amazon||Men's Women's||Men's Women's|
|Product Name||Icebreaker Helix Long Sleeve Zip Hood||Smartwool Double Corbet 120 Jacket|
|Insulation & Fill||70gm MerinoLOFT™, 88% Merino Wool, 12% Polylactide||120g SmartLoft, 75% Wool, 25% Polyester|
|Fit||regular fit||regular fit|
|Best For||lifestyle, travelling, hiking, skiing||travelling, snow sports, lifestyle|
|See Price on Amazon||Men's Women's||Men's Women's|
Smartwool and Icebreaker Product Comparison
Merino Wool Socks
Our first sock comparison is the Icebreaker Hike+ Light Crew Sock vs the Smartwool Hike Light Crew Socks. As well as the similarities in their names, these have a few others that make it hard to choose the best.
Both are designed for moderate walking and hiking, with light cushioning and arch bracing which keeps your sock from slipping down while adding support.
Both also come in 3 sizes for women and 4 sizes for men. Each style has a few different colors to choose from, though Smartwool has a few more options in this area.
There are a few differences in these two socks, though. The Icebreaker pair uses 59% merino wool, 38% nylon, and 3% lycra on both their men's and women's socks.
They have an anatomical fit, so you always know which sock goes on which foot for the best fit. These socks also have a reinforced toe and heel, with Achilles support and a breathe zone for better ventilation.
The Smartwool men's socks use 69% merino wool, 30% nylon, and 1% elastane. The women's socks have 67% merino wool, 32% nylon, and 1% elastane. They have a flat-knit toe seam for added comfort.
The Smartwool socks are also cheaper, but the price can be comparable when you find the Icebreaker's on sale.
Both are great for regular day-to-day wear but don't have a lot of similarities other than that. The Icebreaker crew socks are lightly cushioned, with a breathable weave on the instep and a reinforced heel and toe.
The Icebreaker Lifestyle Crew women's socks come in 3 sizes and one color. The men's have similar features, but an extra size and color to choose from.
The Smartwool Heathered Rib Socks only come in men's sizes of medium, large, and x-large. They have six colors, all with medium cushioning to help absorb the impact.
For the Icebreaker women's Lifestyle sock they choose a material blend of 60% merino wool, 38% nylon, and 2% lycra. Their men's fabric combo is a bit different too, using 67% merino wool, and only 31% nylon, though the lycra content is the same.
The fabric combo of the Smartwool Heathered Rib Socks consists of 61% merino wool, 37% nylon, and 2% elastane.
Merino Wool T-Shirts
Merino wool t-shirts are also a great addition to your gear. With their natural wicking, quick dry performance and antimicrobial properties, they are the perfect match for travel and outdoor adventures.
Plus when against your skin merino helps you feel cooler when it's hot and stay warm when it's cold out.
Both Merino T-shirt models come in men's and women's styles. The Icebreaker men's range from x-small to xxx-large, but the Smartwool t-shirt only goes from small to xx-large. Both women's shirts have sizes x-small to x-large.
Another difference between the genders is the colors. The Icebreaker men's shirt come in 9 colors and the Smartwool men's shirt has 4 to choose from. But the women only have one color, black.
Both brands also use Corespun fabric, which is Merino wool wrapped around the nylon core to increase the durability of the material without sacrificing comfort.
Each shirt also has a dual purpose, as a base layer in the cooler temperatures or a stand-alone when the day warms up.
The seams on both brands are also offset at the shoulders to reduce rubbing when you're wearing a pack, though Smartwool has also added flatlock seams on the sides as well. The shirts are also both breathable and odor-resistant.
Merino Wool Midlayers & Jackets
When it comes to jackets, the Icebreaker Merino Helix Long Sleeve Zip Hood vs the Smartwool Double Corbet 120 Jacket is a great comparison. Each model has both men's and women's styles, though the make is a bit different.
The Icebreaker Helix Jacket is a great lightweight jacket with a regular fit. It comes in both men's and women's sizes, both of which have their unique MerinoLOFT insulation for warmth and breathability.
The Smartwool Double Corbet 120 Jacket also comes in both men's and women's sizes. It also has a regular fit and is meant for colder temperatures.
The panels of the Icebreaker Helix Jacket are polyester, with a mix of polyester, Merino wool, and Lycra over the rest of the jacket, plus it has a DWR finish. The shaped hood keeps you extra warm, as does the storm flap.
Smartwool's Double Corbet Jacket is also polyester on the outer areas, except for the panels, which combine Merino wool, polyester, and elastane. The lining and fill use Merino wool and polyester alone. It has many other features in common as well, including the DWR finish, chin guard and draft flap.
There are two hand pockets and an internal stash pocket on the Helix Jacket, though the updated models replace the latter with an external chest pocket.
The Double Corbet 120 Jacket from Smartwool has similar pockets, though the chest one has a media port.
The Icebreaker Quantum Hoody has a slim fit. Like the Icebreaker model, the Smartwool 250 Base Layer has a slim fit that hugs your body. The shoulder panels have no seams and the seams on the rest of the shirt use Flatlock construction. Together, this eliminates chafing in all these areas.
Very soft and breathable, the Smartwool 250 1/4 Zip Shirt is made of 100% Merino wool, so will be wicking moisture away and keeping you comfy all day long.
The Icebreaker Quantum Hoody is made using mostly Merino wool with a bit of lycra thrown in. These midweight jackets can be used as a mid layer or an outer jacket, depending on the temperature.
The hood on the Icebreaker Quantum is shaped for extra protection from the elements. Chin guards, storm flaps, and a reflective zipper are other safety and comfort features. The underarms are gusseted for added mobility. There are two zippered hand pockets and a zippered chest pocket that has a media port for cords.
Though the Smartwool 250 1/4 Zip has no hood, it has a variety of features that still make it a great choice.
Merino Wool Underwear
Icebreaker Men's Underwear
When it comes to underwear, Icebreaker has its Anatomica line for men, which come in regular, long, relaxed, or ribbed boxers, with or without a fly, and the briefs.
Icebreaker Women's Underwear
For the ladies, Icebreaker has their Siren, Cool-Lite, and Sprite lines. Siren has bikinis and thongs for panties, plus a few bras.
All of these styles have 83% Merino wool, corespun with nylon and lycra for extra durability and strength.
The exception is the men's ribbed boxers, which have 86% merino wool, and the Cool-Lite women's line, which uses only 50% Merino wool and adds Tencel to their fabric.
Smartwool Men's Underwear
The Merino 150's all use 87% Merino wool, but the PhD line varies depending on the underwear you pick. Smartwool also has a couple pairs of long underwear available, with use 100% Merino wool for extra warmth and comfort.
Smartwool Women's Underwear
Women also have the PhD and the Merino 150 lines for their Smartwool underwear choices.
Like the men's PhD line, the Merino wool content varies, depending on whether you choose the seamless boy shorts, bikini, or thong panties. This remains true with the Seamless strappy, racerback, and long bras as well.
The Merino 150 line only has the regular and the micro stripe bikini panties, which both use 87% merino wool combined with a nylon core.
Both brands are quite durable and comfortable, with few complaints from those who buy them.
Some of the Icebreaker underwear may loosen up a bit after a few uses, so most recommend buying them a size smaller. I've noticed this in general with merino wool underwear and they generally wear with a looser feeling than cotton or quick dry underwear.
The Smartwool brands have reports of running a bit big. But either brand you choose should last for years, depending on your use.
How to Choose the Best Merino Wool Socks & Clothing
When you're choosing your new Merino socks and other clothing, you need to consider what you're going to be using them for before you buy.
This is because of the different sizes and thicknesses these garments come in. There are also many different Merino wool clothing brands around to choose from.
So, who makes the best products?
Well, that depends on you. Some brands make their socks a bit thicker than others, while some add more loft.
The fit is also important, which can vary between brands. Some socks also aren't as durable, developing holes faster than others. The same goes for other pieces as well.
The best way to decide on which Merino garments to buy is to check out what others are saying. Read reviews of the products from those who have used them.
You can also check out buying guides, starting with ours below. And it's best to start small, by comparing a few at a time, instead of loading yourself down with a hundred products to compare at once.
That's why we've begun by comparing Icebreaker vs Smartwool. These are two of the best around, so deserve a good look.
About the Brands: Icebreaker vs Smartwool
Icebreaker was founded by Jeremy Moon in 1995. After meeting a Merino sheep farmer, he was inspired to create a more natural product for those who love the outdoors. Since then, they've been the first company to create a natural layering system and to print graphics on their clothing.
Along with making quality products, this company concerns themselves with the animal's welfare. This includes the banning of sheep mulesing, which can be painful and unnecessary.
They have also created a down replacement, reducing the killing of ducks. These are only a few of the ways this company protects the planet and every animal on it.
They source their wool from key growers in New Zealand. Clean water, proper nutrition, open pastures, and plenty of shade are all essential for the health of the sheep. And each one can make up to 5 Icebreaker garments every year.
Smartwool's roots are in Colorado, where cold toes while skiing prompted a need for a better sock. Their Merino yarn comes from sheep raised in New Zealand and Uruguay, but they don't just blindly buy it for their products. They ensure every sheep on these farms are treated well. This means they don't source wool from growers who practice mulesing.
They also trace the wool to each farm to ensure the sheep and the land are properly cared for. Even workers must be treated fairly, or Smartwool takes their business elsewhere. Because of this, its no wonder their values include humanity, humility, integrity, and excellence.
New Zealand Merino Company, a partner of Smartwool, has developed the first Merino wool accreditation program, called ZQ. This program ensures the sustainability of the wool and the protection of the sheep it comes from.
When you check out the pricing comparisons for Icebreaker vs Smartwool, you'll notice that they are pretty close.
There are a few Icebreaker clothing items that are a bit higher in price, but not enough to really change your mind about which brand you're going to buy. This is especially true since both brands are a bit expensive, especially when compared with some other brands.
The reason for this is that both companies use higher quality materials than some of the cheaper brands. Both brands offer products that seem to last quite a long time, so they are well worth the extra money you'll be spending.
Another reason these two have a higher price tag is that they can afford to do a lot of marketing and branding, which affects how much you pay.
Where Are They Made?
If you're trying to decide between Icebreaker vs Smartwool products, where they made might be on your list of things to check.
Icebreaker begins by sourcing their Merino wool from New Zealand. The next step in their process takes place in China, where they clean the wool and prepare it for spinning. Then the products stay in China or are sent to Italy or Bulgaria to be spun into yarn. The next step is the knitting and weaving of the yarn, which happens in a few different Asian countries.
The final step is the garment-making process, which includes knitting the yarn or cutting the panels to be sewn into the products that will be sold. There are five manufacturing areas for this final step, including China, Vietnam, USA, Bangladesh, and Italy.
Though Smartwool gets their Merino wool from the southern hemisphere, their products are actually manufactured almost exclusively in the United States. This means that after the wool is cleaned, combed, and spun into yarn, the mills in the southeast of America manufacture their socks and some of their other products.
But they do outsource some of their products to Korea and other parts of the globe, though it is less than 5% of what they make. Of course, these products are still designed in Boulder at their product development center to maintain their attention to detail.
Warranty is also a key factor in where you should buy your products from, whether choosing between Icebreaker vs Smartwool or considering another brand.
Icebreaker has its Comfort Guarantee, which means if you are not satisfied with any product, you can return it within 90 days for either a replacement product or a refund. Icebreaker warranty also has a Lifetime Sock Guarantee.
This is because the company believes so strongly in the quality of their socks, they believe you will be completely satisfied with it. If you aren't, they'll exchange it for another pair or refund the original purchase.
Here's exactly what Icebreaker says on their website: "At Icebreaker we take pride in the quality of our socks and guarantee 100% satisfaction with your purchase. If for any reason you are not completely satisfied with your socks we will provide you with a new pair or a refund. Please visit your original location of purchase to receive your replacement or refund (proof of purchase is required for refunds)."
I've used Icebreaker's Sock Guarantee a few times after I discovered holes in my Hike Lite Socks and Iceabeaker sent me a new pair---no questions asked. This reason alone is enough for me to solely buy Icebreaker socks, although they are darn comfortable as well!
Icebreaker also has their Damage Warranty. This covers any damage caused by faulty fabric or stitching, or manufacturer defects. This warranty is only for 1 year, though, and offers a replacement but no refunds.
Smartwool has a 100% Satisfaction guarantee for used items, which means that if you are unsatisfied with any of their products, it can be returned within two years of the purchase date. The item will then be replaced with a similar item, depending on the style, function, and price.
This Smartwool warranty doesn't cover limited-edition collaboration products or any product without the Guarantee listed on the packaging or label. This also doesn't cover issues related to normal wear and tear.
Unworn items can be returned within 45 days for a refund or an exchange as part of this Guarantee, so even if you pick the wrong size or color, you aren't stuck with it.
Other Merino Clothing Brands to Consider
L.W. Packard Inc. has been involved in textile manufacturing since 1916. Because of this experience, it only made sense for them to take their love of Merino wool to a new level: clothing. Minus33 was born, with its headquarters in Ashland, New Hampshire.
The company itself employs those who love the outdoors and want to create clothing to meet their needs as well as the needs of like-minded individuals. They specialize in creating quality base layers, with their Chocorua and Kancamagus crew tops and bottoms as their best selling items. Best of all, Minus33 keeps their prices low.
When you love to wear Merino wool, but hate the high cost of it, the only solution is to make your own. That's just what the three Seattle-based founders of Woolly Clothing Co. did. Their goal is to create affordable Merino wool clothing that can replace every other garment in your closet and drawers.
Though they may not have the variety some other brands have, the few hoodies, shirts, and underwear they do sell are all well received. They've even branched out into a few unique items, like blankets and sleep sacks for babies.
After other Merino wool brands fell short of their expectations, the founders of Woolx decided to create their own products that filled the gaps others left open. They rigorously researched the pros and cons of other brands and then used that info to make a better garment.
Their flagship products include their midweight bottoms and 1/4 zip top, as well as their heavyweight hat. Because this company is based in upstate New York, they know what is needed to stay warm and comfy, no matter what activity you favor.
Merino Wool Clothing Buying Guide
What Is Merino Wool?
As its name suggests, Merino wool comes from Merino sheep. This hardy breed originated in Spain but was introduced to Australia in 1797, when the Europeans began settling on this continent.
Since the beginning, Merino wool was prized for numerous reasons. It is finer, bends farther, and has a higher elasticity than other wools. It is also biodegradable and sustainable, so it is safer to use in many ways.
Merino wool is also versatile, meaning it can be used to make a variety of garments. This includes bedding, blankets, and pretty much any type of clothing, from socks to jackets.
Benefits of Merino Wool
Breathable. Merino wool is great because it is extremely breathable. This means that when you sweat, it wicks moisture away from you, letting it evaporate instead of soaking you and your clothing. This also means it regulates your body temperature, releasing heat instead of locking it in.
Static and Stain Resistant. Because the Merino wool absorbs moisture, this also eliminates the static you'd get from other types of wool for less clinging. The outer layer of the Merino fibers also has a protective barrier, which won't absorb stains.
Anti-bacterial. Another benefit of Merino wool is that it has natural anti-bacterial properties. This reduces the odors that normally attach to clothing when you sweat.
Soft. Since the fibers of Merino wool are so fine, this makes it a much softer wool.
Anti-wrinkle. As well as repelling static, Merino wool also has the added benefit of being wrinkle-free. This is because the fibers are more bendable and elastic than other wools, which allows them to hold their natural shape.
Fire Resistant. Merino wool is safer than other fabrics because it is flame retardant, plus it won't melt and stick to your skin in the high heat.
Biodegradable. When it comes time to dispose of your Merino wool garments, they won't harm the planet. This is because it will decompose naturally, providing nutrients to the earth instead of polluting it.
Sustainable. This is probably the best benefit of Merino wool. It continually grows on sheep, so can be replaced every year, with one animal providing countless garments. Most manufacturers also ensure the sheep are well treated, so they will live long, healthy lives.
Is Merino Wool Itchy? Merino vs Cashmere?
One of the top reasons Merino wool is so highly prized is because of its softness. So, no, it is not itchy. But if you are trying to decide between Merino vs Cashmere, you may have a difficult decision on your hands.
This is because both of these fibers are quite soft, though Cashmere is a little softer. This makes it a bit more comfortable to wear, though I have yet to hear anyone complain about the feel of Merino wool against their skin.
But Merino wool is more durable than Cashmere and costs much less, due to the fact that Kashmir goats create only a fraction of the wool a Merino sheep will in a year. So, you pay less for a longer-lasting garment, without sacrificing too much of your comfort level.
How to Wash Merino Wool?
How to wash your Merino wool garments depends on the label, obviously, since some state hand washing only and others don't.
If hand washing is required, do so in a basin or sink filled with warm water and a gentle detergent. Dab stains with a soft cloth. Do not wring it out. Lay it flat to dry to avoid stretching.
For machine washing, the delicate cycle is best, though low to medium heat on a cold cycle also works. Again, a gentle detergent is necessary, but don't use fabric softeners or bleach. Wash it inside out with like colors. Depending on the label, you can tumble dry on low heat or lay it flat to dry.
With both Icebreaker and Smartwool socks and t-shirts I've never run into any problems washing my clothing on cold and hang drying. This is a safe way to go to avoid shrinking and wearing the clothes out too quickly.
What to Consider When Choosing the Best Merino Wool Clothing
When Will You Wear Your Merino Clothes? What Activities?
Whether you're checking out Icebreaker vs Smartwool Merino clothing or another brand, the first thing you need to consider is when you'll be wearing it. The next is what you're going to be wearing it for. Many brands have Merino wool clothing designed for specific activities, like hiking, skiing, or even everyday wear.
You also need to consider the fabric weight. Most layering garments come in lightweight, midweight, and heavyweight layers, which range in thickness and warmth. These garments also come in specific layering options, including base layers, mid layers, and outer layers.
Base layers include things like t-shirts, leggings, or shorts. These are best used for warmer weather or when you're inside, or as the light layers underneath heavier clothing.
Mid layers are hoodies, sweaters, vests, or light jackets that can be worn under heavier layers. These layers work well for cooler days, or as an insulating layer beneath your outer clothing. The outer layers consist of the more padded clothing, like heavier jackets, parkas, or windbreakers. These are great for cold weather activities since they offer you the warmth you need while still maintaining your mobility.
100% Merino vs Blends
Though Merino wool is soft, breathable, and comfortable to wear, unfortunately, it isn't strong. This is why most manufacturers don't use Merino wool alone when they make their clothing. Instead, they blend it with other fabrics to increase the strength of the weave.
The main materials used for this blending are either nylon or polyester. Sometimes they use smaller percentages of the other materials, though they may go as high as 50% of the blend and 50% Merino.
But though the material may be stronger, this does decrease the breathability and antimicrobial function higher Merino wool content will have.
Another thing to consider is the fabric density, or thickness, of the Merino wool. This density usually ranges from 135 g/m2 to 400 g/m2.
The thicker the fabric, the warmer it will be, so keep this in mind when choosing your clothing. You don't want a thick 350 g/m2 shirt for a warm summer day. But the thinner density also reduces the durability, so those clothes may not last as long.
When it comes to choosing your clothing, the fit is one of the most important things to consider. This is because a piece of clothing that doesn't fit right won't be comfortable, so you won't wear it.
Merino wool has a tendency to fit a bit more snugly than other fabrics, so some have found this to be an issue.
But this doesn't mean you should avoid it if you are a bit bigger, it only means you may have to size up when you buy it.
You also need to consider what layer you're choosing. Things like underwear or base layers are meant to fit snugly.
For the base layers, this is especially important since it is meant to wick the moisture away, which it can't do if it isn't touching your skin. If it is looser, it will also trap more of the heat in, so you may be warmer than you expected to be.
For outer layers, it depends on what you're going to be doing. A bulky coat is fine for strolling to the store, but if you need mobility for running, climbing, or hitting the slopes, a slimmer fit is a must.
Whether you're trying to decide between Icebreaker vs Smartwool or you have another brand in mind, you need to consider the garments durability.
As we discussed above, Merino wool isn't very strong on its own, which is why it is usually blended with other fabrics.
But there are ways you can increase the life of your Merino wool clothing. First of all, try to wash it less frequently. Because the material won't absorb odors like other material will, you can probably wear it a few times before it needs to be cleaned.
When you do wash it, be sure to follow the instructions on the label. Though some garments may say it is safe to put them in the dryer, laying them flat is a better choice. Heat can damage the wool over time, so avoid it whenever possible.
Sharp objects will tear Merino wool very easily, so try to keep your Merino clothing safe from these tears and abrasions.
This may mean choosing other clothing when hiking in densely treed areas or at least covering them with another piece of clothing. If a tear does happen, stitch it up as soon as you can to avoid it spreading.
We've already compared the warranties of Icebreaker vs Smartwool, but you need to consider the warranty of other brands you choose as well.
Many companies offer some sort of guarantee, which allows you to return unused or lightly used clothing for a certain amount of time after purchase. This means you can swap it out if you don't like the fit or find it uncomfortable to wear for any reason.
Some also have a warranty against any manufacturer's defects. This is very important since you won't want to keep a garment that isn't up to the company's own standard, much less your own.
Some companies also have certain warranty options for specific garments that don't cover every piece they sell. Be sure you know exactly what you're covered for before you buy any piece of clothing.
Merino wool products, in general, are more expensive than other types of fabrics. But you won't necessarily have to pay hundreds of dollars to find a decent piece of Merino wool clothing.
Those that are blended with other fabrics may be a bit cheaper for starters, while 100% Merino wool clothing comes with a higher price tag.
You also have to check out a few different brands. For instance, in our Icebreaker vs Smartwool comparisons, though many of the pieces were similar in make and style, the Icebreaker brand was a bit more expensive in every category. Though this may reflect a higher Merino wool content in some instances, this isn't always the case.
Another thing to consider is sales. Items that are low-selling or being discontinued will drop in price if the company is trying to reduce the stock. There are also certain times of the year when sales happen on everything, like Black Friday. If you can wait to buy, you may save some money in the end.
Icebreaker vs Smartwool - Who Makes the Best Merino Wool Clothing?
When it comes down to deciding which is the best company, Icebreaker vs Smartwool, and who makes the best products, it isn't an easy choice.
Both companies pride themselves on the safe practices and Merino wool sourcing. But they do have a few differences in their products to note.
First of all, most of Icebreaker's products are more expensive than similar models sold by Smartwool. But this may have something to do with the features some of their products sport.
For instance, in the sock category, the Icebreaker socks are more durable, with reinforcements on key areas, like the heel and toes, and Achilles support. Personally I've a Icebreaker sock guy. Plus they will replace them, no questions asked, with their lifetime sock guarantee.
In the T-shirt category, though Smartwool adds Flatlock seams on the sides as well as the shoulders, the Icebreaker models have a few extra sizes and colors to choose from. Although they may be a bit more pricey, my pick for the best merino t-shirts goes to Icebreaker as well. I've traveled with my Tech T Lite shirts for 4+ years and they are just now starting to show wear.
The underwear is pretty similar, though Icebreaker offers a few more options for women and Smartwool adds long underwear for the men, so it all depends on what you're looking for. It mostly comes down to fit and feel, so you may have to give them a try to find your favorite.
The jackets we compared were also quite similar, so it is hard to pick a favorite, though the Smartwool Double Corbet 120 is cheaper and has that media port. In most regards and performance it's comparable to the Icebreaker Helix. Both are incredible warm and lightweight.
For the midlayers, the Smartwool Merino 250 Base Layer 1/4 Zip lacks the hood found on the Icebreaker model, though the Flatlock seam construction reduces chafing.