Baffin's polar-proven APEX Men's boots are rated to perform at -100°C/-148°F., tested at both the North and South Poles. Doubled B-Tek insulation, a double aluminum insole and a waffle-comb foot-bed trap warm air produced by your body and keep the cold out. The leather upper is waterproof. The liner is a removable multi-layer inner boot system. an Arctic rubber shell and Polar rubber outsole keep moisture and snow out. A speed lace system and full-length tongue get you in and out of the boot quickly and securely.