≪ Go to our review of Long Underwear - Men's
Hands-on Gear Review
Rab Merino+ 160 Review
Cons: Not very warm, low durability
Bottom line: Our Top Pick for Lightweight, the Rab Merino+ 160 is a champ of moderate temperatures, with an excellent fit and comfort, great breathability, and a fast drying fabric in a lightweight package.
Fabric Weight: 160 g/m 2
Weight (size M): 7.5 oz
We were psyched to try out the Rab Merino+ 160. The blend of merino wool and polyester, combined with a slick look and lightweight, is what caught our initial attention. Putting this base layer on over our heads, we were impressed with its comfort and slim fit. Through our trips to the backcountry, we loved the exceptional breathability and fast drying speed of this thin top. It's not mega warm, but it was exactly what many fall and spring conditions called for. Our biggest complaint was its durability, which we found to be lacking. However, its excellent performance in most other categories and lightweightedness convinced us of its exceptional merit, therefore winning our Top Pick for Lightweight.
We featured some other comparable models to the Rab in our review. If you are into blended fabrics but prefer one with more warmth, you might find the tasc Base Layer intriguing. Or, if the price tag of this model is simply too much, be sure to have a look at our Best Buy award-winning The North Face Warm. For all eleven products, we ran through the gauntlet of tests and outdoor use, see our full Men's Long Underwear Review.
RELATED REVIEW: The Best Long Underwear and Base Layer for Men
Our Analysis and Hands-on Test Results
The blended fabric and thoughtful design of the Merino+ 160 more than convinced us over our testing period that this model deserves applause. Weighing only 7.5 oz and featuring a fabric weight of 160 g/m², it provides excellent breathability, superior comfort, and a surprisingly good layering ability. It's not extremely warm, but if you don't need the extra insulation, our Top Pick for Lightweight is a smart choice. It does cost $110, which was the second-most expensive long underwear top in our laundry heap.
We don't all live in the arctic circle, or Minnesota, and therefore probably don't need the warmest base layer for a great deal of our three-season adventures. Enter the Merino+ 160. With a fabric weight of 160 g/m², it is suited for fall, spring, and the edges of winter. On its own, we were able to wear it down to 40-45°F while remaining moderately active. That's actually warmer than the Patagonia Capilene Midweight, a synthetic model of the same fabric weight. We hiked in temperatures hitting the mid-70s without any problems, too. If warmth is what you're after, the Arc'teryx Rho was the only contender to score a 9 out of 10 in this metric, with the Smartwool Merino 250 trailing behind, scoring an 8 out of 10.
If you don't spend large amounts of time inactive in cold temperatures, this is a great model for your consideration.
Several design details added some warmth in more subtle ways. The superior fit of this model helped to control the microclimate between our skin and the shirt. With long sleeves and an adequate torso length, our wrists and bellies were never exposed to cool air when moving through the backcountry, which is much more than the Icebreaker Oasis can say. This model also has a drop tail for a happier bum and to help it stay tucked into pants. The back of the zipper teeth are prevented from skin contact by an extra strip of material sewn in place, and the metal slider pull tab won't unpleasantly chill your neck due to a sleek zipper garage.
This thin fabric was one of the best in our base layer selection for transmitting moisture away from our bodies. In the backcountry, we hiked for hours on end with a heavy pack in moderate temperatures, but never felt any sweat condensing on the inside of this shirt. Any moisture we produced was immediately moved to the external environment. Its performance was comparable to that of the Patagonia Capilene, Icebreaker Oasis, tasc Base Layer, and REI Merino Midweight models.
In our indoor workout test, we worked up a good sweat, but it only took five minutes to be back to dry inside this master of exhalation. The Helly Hansen Lifa Stripe Crew and Under Armour Base 4.0 were more breathable, and only slightly. In all, this shirt does very little to deny the laws of thermodynamics, and we love that.
Comfort and Fit
We like the design and placement of the flatlock seams. They are thinner than most of the other models, and placed strategically to avoid chafing anywhere, such as the shoulders and under the arms. The huge gussets along the sides and under the arms attributed to this top's unhindered mobility. Due to its weight, fit, and superior design, this model felt the least restricted of the whole lot. Nice work, Rab! The only product that topped it in terms of comfort was the incredibly soft SmartWool Merino 250 Base Layer. Like the SmartWool, the Merino+ was one of the best-looking tops for around town, too.
After thoroughly saturating this shirt, it took 13 hours to completely dry, only 8% slower than the fast-drying champion, the Lifa Stripe Crew. We credit its thin fabric to a large part of its success. If you ever manage to sweat more than this breathable top can handle, rest assured that it will dry faster than the majority of alternatives.
While we don't expect our base layers to become completely saturated very often in the backcountry, we think this extreme test provides good insight on how these tops perform when wet or when you're sweating.
The biggest drawback of this Rab top lies in its weak durability. Starting with the fabric, despite being reinforced with 35% polyester, it feels less sturdy than the fully synthetic Capilene Midweight, its fabric weight equal. However, after three months of extensive use and abuse, we didn't find any wear nor tear in the fabric.
The seams were another story, though, and a large reason this product scored low in this category. The hems at the bottom of the sleeves and the shirt bottom are especially susceptible to ripping and tearing loose. We found several points where the threads were coming loose at the end of our testing period; although it didn't have any effect on the performance of this top yet, we expect that it will come at some point down the road. Also, the flatlock seams didn't instill us with great confidence in terms of their longevity. We liked the solid seams on The North Face Warm and Icebreaker Oasis much better for their durability. We think this already great product could increase its value by putting a little more care and sewing mastery into its seams.
Manufacturers of blended fabric base layers like to boast that their products are more durable than traditionally delicate wool models. In our testing and use of wool, synthetic, and blended fabric long underwear, though, the blended models turned out to be the least durable of the bunch.
For being a thin, slim-fitting product, the Rab 160 model gets along well with others. It slides under mid-layers and jackets easily, and stays in place when moving around as a first layer. It also stretches nicely to fit over next-to-skin t-shirts and base layers with minimal bunching in the armpits. We didn't notice any loss of mobility when layering, but it did lose a bit of comfort when layered over other products. It won't fit over thicker base layers very well, either. But then, why would you want it to?
Although this product does fit over other thin base layers, we would generally recommend a thicker product for your mid-layer to get more performance out of your layering system.
The Arc'teryx Rho AR was the best model for layering under and over all kinds of thick and thin layers. The Editors' Choice winning SmartWool 250 was also superior to the Rab 160 model in layering ability.
We recommend this base layer for almost any form of activity in cool temperatures, and even moderate activity in warm environments. Fall and spring are the perfect seasons for the Merino+ 160. Being quick to dry, this is also a good option for wetter, sweatier climates where you need a base layer, as well as water sports such as kayaking or canoeing trips. It resists odors fairly well, and looks good too, making it a good option for time in the backcountry and around town.
This product isn't cheap, costing $110. We think that's a lot to spend on a shirt, but if you want top performance from a lightweight base layer, you won't find a better model than this one. Rab seems to have a penchant for high-quality designs, and their prices follow suit. Although it is expensive, we still find a lot of value in this excellent product.
We are big fans of the Merino+ 160 by Rab, as we appreciated a model that could handle the upper range of temperatures for base layer use very well. It breathes incredibly well, dries fast, and fits and feels great on our torsos. We liked the good looks this model provides when moving around social and urban environments, too. If these are qualities you want in your next base layer, we highly recommend our Top Pick for Lightweight.
— Ross Robinson
You Might Also Like
The Best Long Underwear and Base Layer for MenLong underwear options are seemingly overflowing from the shelves. With so many choices, we researched more than 80...
OutdoorGearLab Member Reviews
Most recent review: December 19, 2016
Where's the Best Price?
*You help support OutdoorGearLab's product testing and reviews by purchasing from our retail partners.
Table of Contents
Other Gear by Rab