When other hikers start turning back, you keep going strong in comfort with the help of the Darn Tough Mountaineering Over-The-Calf Extra Cushion Sock. This sock features a heavyweight merino wool blend and thick cushioning to help you laugh in the face of icy winds, sideways sleet, and treacherous terrain. Unlike other socks built for extreme weather, this one features Darn Tough's streamlined performance fit so it still fits comfortably in your boot. Merino wool regulates temperature to maintain comfort from the trailhead to the peak, nylon adds durability, and Lycra maintains stretch and recovery so the fit doesn't fade over time. This sock also features Darn Tough's thickest, highest-density cushioning to ease impacts from rugged terrain and ease the burden of fully-loaded packs.