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. Mold-on rubber wheels are quiet, even under a heavy load and have a low initial roll effort. Great for floor protection. 4-1/2 x 3-7/8 plate size. 2-5/8 to 3 x 3 to 3-5/8 bolt spacing.