MADE IN THE USA. Super Heavy Duty Office Chair Base Pedestal with load capacity 500 pounds. This replacement office chair base is ideal for large chairs with swivel / tilt / rocking plate. It is made of Solid Cast High Grade Aluminum and FAR exceeds BIFMA standards. It has an outside diameter of 28". The legs have a standard hole of 7/16” in diameter for casters. The center hole starts out at 50mm (1.96”) and tapers down. 5 heavy duty casters included in price.