New ergonomic design gives you higher quality, better performance and greater durability. Permanent .625 rivet kingpin construction featuring full double ball raceways with grease fittings. Polyurethane casters have an extended life with excellent mobility. The cushioned ride protects the load and floors. 4-1/2 x 3-7/8 plate size. 2-5/8 to 3 x 3 to 3-5/8 bolt spacing.