Excellent socks for multi-day backpacking with all the comfort in mind. Light Ventum socks features:; Asymmetric venting keeps feet cool in warm conditions. Dorsal ridge pad with a differential cuff for added protection. Sweeping mesh cools the foot. Boot height cut. Anti-microbial freshness. Fast Ventum socks features:; High density for cushioning and impact protection. Cuff line height for ankle protection. Anti-microbial protection. Heel lock for no slip fit. Ultra breathable mesh top. Consists of 41% merino wool, 33% polyester, 23% nylon, 3% Lycra(R); Wash inside out with dark colors, tumble dry low. Available in a 3 pair variety pack.