INDUSTRIAL GRADE CASTERS：The heavy duty steel casters are made of high-quality mixed of Steel(Felixible)with strong Cast Iron hub, bright galvanized steel wheels and zinc plated finished yoke. The Heavy Duty Steel wheels have strong abrasion resistance are not easy to rust.Cast Iron Caster has strong shock absorption and buffering performance, which increases the service life. HIGH CAPACITY: Industrial caster wheel 4 inch diameter, 2 inch width, top plate: 4"x 4-1/2", caster overall height: 5-5/8", with ¾” roller bearing,and ½" ID spanner bushing with Zerk Axle,One caster can be loaded up to 800lbs, strong load-bearing capacity, so you can buy and use with confidence. Conquer Demanding Industrial Settings ：Cast iron casters have an extremely long life and can withstand extreme temperatures from -45F to 600F. Recommended for objects that are not frequently moved on rough wood or concrete floors. WIDELY USED：These casters are great for dollies, plat-form trucks, warehouse carts and freight terminals. Our heavy duty high quality medium heavy duty casters are well-suited for most all industrial and commercial equipment. Also recommended and installed on drywall carts, welding carts, and wall panel carts and much more! WHAT YOU GET: Provide professional industrial caster solutions, in addition, Provide Axle & nuts, yoke and wheel replacement severice any time. GRAY IRON SEMI STEEL WHEEL