Listing is for a set of four (4) Service Caster Series #30 316 stainless steel casters, two (2) swivel casters with bolt on swivel locks and two (2) swivel casters with top lock brakes, with 4" diameter by 2" wide polyurethane on aluminum wheel and maintenance free precision ball wheel bearings capable of supporting a total weight of 2,800 lbs. (700 lbs./caster). When searching for a reliable and durable solution to your caster needs, rely on Service Caster Series 30 316 stainless steel polyurethane aluminum casters. The Series #30 features heavy duty polyurethane wheels that are chemically bonded to an aluminum core, providing a smooth roll over uneven surfaces without marking or marring floors. Finely crafted with a heat-treated ball bearing raceway, these versatile casters are ideal for a wide range of applications. Use on dollies, platform trucks, warehouse carts and freight terminals, or ensure a smooth and secure ride for food service carts, hotel housekeeping carts, and industrial and commercial equipment. In contrast to the zinc plated caster, the luxuriously polished stainless steel finish resists rust and corrosion in indoor or outdoor applications where moisture is a factor. Service Caster is unsurpassed in quality, reliability, and excellent customer service. Count on us to move you forward.