Sorel Toddler Flurry TP Winter Boot (Toddler) 100% Polyurethane, Synthetic, Textile Rubber sole Upper: Durable water and wind resistant PU coated synthetic textile upper. Built in gaiter with barrel lock closure system and fixed elastic instep strap Insulation: Removable 6 mm ThermoPlus washable, recycled felt inner boot Midsole: 2.5 mm bonded felt frost plug Outsole: Injection molded waterproof thermal rubber shell with multi-directional lug outsole for enhanced traction