The Danner TFX Hot Weather DryMax socks use a dual layer moisture removal system. The system uses DryMax fibers against the skin to instantly move moisture to an absorbent outer layer keeping your feet dry and healthy all day long. Drymax wicks away moisture to keep feet up to 25 times drier than polyester, acrylic, nylon or wool. Microzap silver in Drymax is anti-microbial for odor control. 52% Polyester, 27% Drymax Olefin, 12% Elastane, 9% Nylon.SizingSmall >6Medium 6-8.5Large 9-12.5XL 13-15FeaturesDryman removes moisture to keep up to 25 times fasterAnti-microbial odor control