FastDry with 37.5 technology makes this garment our fastest drying piece. The 37.5 technology fiber absorbs and releases sweat and is integrated into the fabric; it does not wash out. Odor-resistant. The 37.5 technology fiber maintains your optimal body temperature to prevent sweating. Semi-cushioned foot for added comfort. Ribbed, elastic fabric at the ankle and arch provides support and ensures that the socks stay in place. Reinforced heel and toe area for extra durability. Elastane ensures the perfect fit.