SIMMS GUIDE GUARD SOCKS - Perforated airprene throughout allows water to drain and provides breathability to keep feet comfortable in the water and on the trail. 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 on/off. Built-in gravel guard. SIZES: S(7-8), M(8-10), L(10-12), XL(12-13)