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.
Our Top Pick award winner from Rab epitomized the best of lightweight models.
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.
With a light jacket and low to moderate activity, this base layer was sufficiently warm in temperatures teetering between cool and cold.
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
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.
Even when hiking on a sunny day in a Peruvian desert canyon with a heavy pack, this top refused to get sweaty.
Comfort and Fit
Just as the warmth of this top benefits from its great fit, so does its comfort. The Rab model is very flexible, and sits comfortably next-to-skin on our torsos. It's not too tight, and not too loose. Its sleeves are longer than several other models, especially the Icebreaker Oasis
, which had very short sleeves. We were able to climb rocks, perform jumping jacks, and give emphatic high-fives to our friends without the sleeves riding up our arms. This was a frequent problem with other base layers, and we are super glad this top didn't have that annoyance. It doesn't build up static electricity, either, and feels great when in contact with our skin.
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.
Hillside calisthenics! Testing our the mobility of this top, luckily with no one around to see us...
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.
If you get caught in the rain, or work up a considerable sweat in this top, rest assured that it will dry faster than any other model we tested.
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.
After three months of activity, the Merino+ 160 began showing signs of wear. We wish this great product could last forever! But, reality, man.
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.
This product had lots of upsides. Not only could the Rab model fit easily under jackets and mid-layers, it stretched over t-shirts well, too.
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, but once you bite the bullet, you'll be psyched to wear it.
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.
Doesn't he look happy? That's the look of you might get when you match the right top for the environment and activity.
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.