This 8" x 2-1/2" Thermoplastic Round Gray Tread Rigid Caster consists of heavy pressed rich-quality, chromium-nickel stainless steel. This caster is made with Axle materials that are corrosion-resistant and a Bolted wheel axle. Vibration-ground finished. This caster includes rich-quality thermoplastic polyurethane, high operational pleasure, low-noise operation, proper floor preservation, and extremely high chafting resistance. In addition it is chemically bonded for an indivisible linkage to the wheel center.