Merrell Men's Whiteout XT6 Waterproof leather-and-mesh TPU Waterproof half shell Waterproof membrane provides impermeable but breathable barrier 200 grams Merrell Opti-Warm lightweight, low-bulk, insulation keeps you warm Internal Merrell air cushion in the heel absorbs shock and adds stability with an EVA midsole for cushioning Merrell Active Heat inSole with silver reflective film for added warmth