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Black Diamond Solution 150 Merino Base 3/4

rated 4.5 of 5 stars
photo: Black Diamond Solution 150 Merino Base 3/4 base layer bottom

Black Diamond's Solution 150 Merino Base 3/4 is a lightweight, polyester-reinforced merino wool base layer. Cool enough to wear under light shell clothing for high intensity activity at around-freezing temperatures without overheating, but easily layered over for use in colder conditions or at lower intensity. Stretch fabric gives a comfortable fit even on a slim frame and dries a little faster than 100 percent merino. 3/4 length works with high plastic cuff ski boots.


  • Comfy fit and feel
  • Light base layer for intensive activity
  • Also good for cold-wet days in summer
  • Lightweight in the pack
  • 3/4 length works with tele and rando boots and saves a little weight


  • Polyester core may shed microplastic fibers in wash water
  • No long sizes

(Preliminary review based on the first month of use)

Black Diamond’s Solution 150 Base shirts and long underwear are lightweight, polyester-reinforced merino wool base layers. They are light enough to wear under light shell clothing for high intensity activity at around-freezing temperatures without overheating, but easily layered over for use in colder conditions or at lower intensity.

BD has supplied me with both a crew neck top and ¾ length bottoms for testing. Much of what I have to say about the one will apply to the other and so may be duplicated in both reviews.  The Solution 150 lineup also includes a full length bottom, and all three variants are also available in women's versions.


Usage (so far)

I have been using the Solution top and bottoms as my base layer on about 30 days worth of outings so far, mainly for 1-4 hour xc ski tours at a high energy level, but also some winter trail running and hut-based backcountry skiing including some lounging around wood-heated Norwegian huts.

Material Matters

Rather than pure merino wool, BD’s NuYarn has a 22 percent stretch polyester core wrapped in fine merino wool to give a stretchy, thin knit fabric that weighs in at a light 150 grams per square meter. BD claims it is stronger and warmer and will dry faster than other merino wool fabrics while maintaining merino's odor resistance.

My trial pair has a classy gray flannel look, currently the only color choice.The knit fabric feels a bit thinner and lighter than some of my other merino layers, a welcome difference for me because I sometimes overheat. The fine merino wool feels good on the skin, with none of the itchiness that comes with some wool garments. Strategically placed flat seams and a flat elastic waist band minimize rubs and pressure points under a pack waist belt. The close stretch fit makes it easy to layer over with stretch fleece or other close-fitting layers.

Like pure merino, NuYarn has proved to be smell-resistant. I prefer to hand wash my woolies, and that infrequently, to extend their life, although BD allows gentle machine washing. So far, I have washed the Solution duo only once. Intensive activity inevitably involves some sweating, and, like my pure merino tops, these layers have absorbed a lot of sweat without any noticeable BO buildup or that wash-resistant smell that plagues polyester base wear.

The polyester core may help give a longer life. Despite all its warm, smell-free wonders, 100 percent merino can get threadbare and develop small holes after a few seasons of hard use. Only time and use can tell whether the NuYarn blend will hold up any better.

BD also claims that NuYarn dries faster than pure merino. I did a comparative passive drying test of the Solution 150 crew neck top along with some pure merino and synthetic tops (full report in my review of the Solution 150 Crew), and found that it dries faster than a newish and somewhat heavier and warmer merino top, but a bit slower than worn merino or synthetic shirts. With the added push of body heat under other layers, sweat-soaked Solution 150 will dry out nicely during an hour or so of reduced activity.

My size M weighs in at 129 g and rolls down to the size of two fists so it won’t take up much space in the pack when taken along on summer trips.

Fit and Comfort


Being tall and thin, getting outdoor clothes that fit is always a concern for me. I have another pair of 3/4s that are a bit short and pull partly up over my knee, sometimes exposing a little skin over my knee socks. BD’s sizing chart puts my waist size right on the S/M boundary, but at L or XL when it comes to leg length. Fortunately, the ¾ Solutions in a medium are a pretty good fit on me, close to the skin all around and long enough to stay down over the knee. I would prefer a medium long size for an even better fit, but the stretch knit fabric should accommodate a wide variety of body types that are closer to average proportions than I am. Unlike some men's underwear, the 3/4 bottoms do not have a front opening, not really an issue for me because I've always been one just to pull the waistband down.

Temperature Range

Temperatures during use so far ranged from about -8 to +5˚C (18 to 40˚F). At the upper end of that range the ¾ bottoms are too warm to wear under light warm-ups for high-output xc skiing, when I would normally just full-length tights unless it is very windy. Worn under waterproof-breathable bibs with knee socks and with suitable upper body layers, the Solution top and bottom are ideal for backcountry skiing temperatures down to -10˚C (14˚F) or maybe a bit lower.

Based on experience with other wool base layers, I think the Solution 3/4s, worn under rain gear or shorts, would also work well for hiking in cold mountain rain in summer or as evening wear around camp. The lightweight fabric and weight savings of the ¾ length are a plus for gram-shavers.

Conclusion (so far)

I am very happy with the fit, comfort, and performance of the BD Solution 150 lineup as a base layer for moderate to high activity in cold weather, such as backcountry and xc skiing. I will continue using it for the rest of the ski season and report back in the spring.


About a month's use so far, including about three weeks of daily/nightly xc ski tours while we had good snow, three hut trips, and some icy trail runs. These are the latest in a lifetime of long underwear, dating back to the cotton wafflewear I wore as a kid.

Source: received for testing via the Trailspace Review Corps (Sample for testing and review provided by Black Diamond)

About the Author

Rick Strimbeck is an American transplanted to Norway where he says he'll "never run out of mountains." He is a veteran backpacker and expert nordic and backcountry skier and in summer runs, hikes, kayaks, and canoes in Norway's mountains and fjords and elsewhere in Europe and the U.S. When he's not outside, he does research on Norway's trees and alpine plants and teaches as a professor at the Norwegian University of Science and Technology in Trondheim.

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