Medium Duty Casters Wheel Options: (4", 5", 6", 8") Rubber Tread on Iron (Black on Black Iron) Polyurethane (Red on Silver Semi-Steel) Semi Steel with Bearing (Silver) Polyolefin (Black) Phenolic...

General Duty Casters Wheel Options: Hard Rubber Semi Steel with Bearing Semi Steel without Bearing Polyolefin Rubber Tread on Iron