Apply over fiber cement board or green board in wet areas (tubs, showers, tile countertops, tub decks) to make seams and corners watertight. Produces straight, strong, and waterproof inside and outside corners. Useful for inside 90 deg. corners and intricate off angles, and inside 90 deg. corners where a large fill is required. Will not cut or snag with notched trowel when applying tile setting compound. Color: Ocean blue. 2-1/4" W. x 100'L. roll.