CastleMats Flower Mat 4 Doormat, Non-Slip, Durable, Made Using Odor-Free Natural Fibers, 18" L x 30" W Great for indoor and outdoor use: This 18 x 30 inch doormat, 1/2 inch thick, contains a waterproof rubber backing that is gentle on indoor flooring Traps dirt & mud: The top is layered with coarse fibers, which quickly absorbs water and dirt from wet shoes Easy to clean: Odor-free natural fibers quickly dry and resist buildup of mold and mildew Non-slip surface: The nonskid rubber backing ensures your doormat stays firmly in place on the floor