Patent-pending Alpha Technology. Rubber-clad neoprene for ultra lightweight comfort with 100% waterproof protection. 800 gram Thinsulate Ultra Insulation for ultimate warmth. Naturally insulating 3.5mm neoprene provides warmth. 100% ozone-resistant and scent-free rubber. Sport Chassis outsole system cradles your foot for all-day walking comfort and provides torque stability on uneven terrain. Double-reinforced toe and heel. EVA midsole and footbed for all-day cushioning comfort. Fleece lined for moisture management. Back gusset with Cam-Loc buckle design for bulky clothing or larger calves. Fiberglass shank for lightweight arch support.