Northwave Extreme H2O Shoe Covers Black. Made with a waterproof polyester lining lined with fleece, sealed to prevent water infiltration. Its sole is reinforced with rubber. The heel is reinforced with a large reflective insert. Reflective zipper with puller to improve visibility. The flap covers the zipper puller to prevent water penetration. The closed sole prevents the entry of water and optimizes insulation and warmth. Aerodynamic pattern.