U.S. Merino Wool: We source our 100% U.S. grown merino wool exclusively from sheep raised by American farmers on American farms. Merino wool keeps you cool in the summer and warm in winter. Reinforcing yarns woven into the stretch shell increase durability, while wool fibers sit closer to the skin for maximum insulation Bottom-of-foot cushioning across the entire sole provides shock-absorption that reduces impact from running and hiking and fitted instep reduces bulk Half-Density Cushioning: On the inside of the sock, a terry knit loop every other stitch creates half-density cushioning to add softness without dramatically affecting sock thickness. Its lower density makes it ideal for casual socks. Seamless Toe Closure: Advanced knitting techniques create a totally flat connection in the toe box, reducing bulk and eliminating blister-generating friction. The Boulder is a traditional hiking sock that has exactly what you need: durability, comfort, and all-season versatility. Outer plaiting construction gives it durability and that classic hiker look, while placing more body yarn next to the skin for improved wicking and insulation. Full-density padding along the instep and up the shaft makes it comfortable to wear with lace-up hiking boots.