Listing is for a set of four (4) Service Caster Series #30 casters with a 8" diameter, 2" wide thermoplastic rubber tread on polyolefin core wheel and maintenance free precision ball wheel bearings. Set includes two (2) rigid casters and two (2) swivel casters fitted with top locking brakes . Supports 2400 total pounds (lbs) at 600 pounds (lbs) per caster. When searching for a reliable and durable solution for medium and heavy duty projects, consider Service Caster?s Series 30 top plate thermoplastic rubber flat tread on polyolefin core casters. The soft flat tread is made of thermoplastic rubber that is non-marking and non-marring, and on the polyolefin core provides a long lasting, high capacity wheel that is capable of easy rolling under heavy loads. Finely crafted with double ball bearing heat treated raceways, these versatile casters are ideal for a wide range of applications, such as 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. Even drywall carts, welding carts, and wall panel carts will be ready to roll on the Series 30, keeping you moving forward. Service Caster is unsurpassed in quality, reliability, and excellent customer service. Count on us to move you forward.