Durable water and wind resistant PU coated synthetic textile upper. Drawstring with barrel lock closure. Removable 9mm felt inner boot with Omni-Heat reflective lining, 2.5mm bonded felt frost plug. Sealed 6mm Thermo Plus felt midsole for added warmth. Waterproof vulcanized rubber shell with Sorel aero-trac non loading outsole. Rated -51.5 C.