The Black Diamond Solution 150 Merino Base Crew is the crucial lightweight warm layer you need in the brisk alpine mornings. Designed to be stronger, warmer, and dry faster than other merino fabrics by wrapping a nylon core with extra fine merino fiber. The Solution 150 Merino Base Crew is naturally antibacterial, and odor resistant. The flatlock stitching provides all day comfort, and comes standard with comfy thumb holes.