This 4" x 2" polypropylene heavy duty swivel caster has a one piece plastic wheel ideal for use in wet and chemical environments. Polypropylene is non-reactive and non-marking. Our 45 Series is an economical lineup of casters and wheels designed for a range of applications with load requirements ranging from 300 to 1,250 pounds per caster. From shop carts to containers, to platform and lumber carts the 45 Series is the most competitive and in-stock 2" wide solution.