Waterproof membrane seals out water and lets moisture escape. Waterproof full grain leather and knit upper. Protective and abrasion resistant rubber heel and toe cap.100 grams Primaloft® Gold Eco Series synthetic insulation. SOLARCORE® insulation with Aerogel provides underfoot superior warmth while being extremely flexible and ultra-thin. FloatPro™ Foam midsole for lightweight comfort that lasts. Vibram® IceTrek outsole designed to provide the improved grip on very cold, icy, or snowy surfaces.