Ideal for days when waders aren't necessary, the Guide Guard socks provide comfort and warmth inside of Simms wading boots Constructed using 3.5mm abrasion-resistant neoprene in the upper and gravel guard, and perforated 3.5mm neoprene underfoot for drainage Anatomically correct left and right patterning for superb fit and easy don/doff Fold down gravel guard includes boot hook for security Unisex sizing: XS (M's 4-5, W's 6-7) S (M's 6-7, W's 8-9) M (M's 8-9, W's 10-11) L (M's 10-11, W's 12-13) XL (M's 12+) FABRIC TECH: 3.5mm neoprene ITEM #: PG-13503