Install this rigid urethane-plated zinc caster, with its six-inch diameter, two-inch wide wheel, on equipment that needs to be moved frequently. Its load rating is 900 pounds, and it is intended for medium-duty usage. Install this grey, rigid caster on equipment with 3/8-inch mounting bolts on its 4 x 4 1/2 mounting plate, with outside bolt hole spacing of 3 x 3 5/8 inches. When needed, use replacement wheel 5-6-921 SS for repairs.