Shepherd 6 In. Heavy-Duty Polypropylene Rigid Plate CasterRigid industrial medium heavy duty caster, 400 Series. Polypropylene wheels give easy mobility to heavy loads on smooth hard surfaces. The wheels are nonmarking, light in weight, and have high impact strength. They resist water and chemical absorption. Its versatility makes it ideal for most general medium heavy duty industrial applications. Ideal for platform trucks, wire shelving, warehouse trucks, and carts. Fasteners not included. %search_data%3123