New and improved anatomical fit adds comfort and reduces weight. 2.5mm abrasion-resistant neoprene in the upper, and perforated 2.5mm neoprene underfoot for drainage. 2.5mm airprene in the underfoot allows feet to breathe and reduces unwanted odors. Anatomically correct left and right patterning for superb fit and easy on/off. Same 2.5mm construction as Simms standard Wading Sock, with built-in gravel guard to shed water, gravel and muck. Silicone print grip inside gravel guard and reinforced lace hook to keep it in place. Mid-calf height.