Listing is for 1 (one) service caster series #30 caster set of four casters; 2 swivel casters with brakes and 2 swivel casters fitted with 6 inch diameter by 2 inch wide, non-marking polyurethane tread on polyolefin core wheel. Quality casters featuring double ball bearing heat-treated raceways(swivel SCC-30CS620-PPUR-2-TLB-2 only), bright Zinc plating, grease fittings and "( 625 inch) bolted kingpins (swivel SCC-30CS620-PPUR-2-TLB-2 only). these casters are ideal for dollies, platform trucks, warehouse carts and freight terminals. Series #30 medium heavy duty casters are well-suited for food service carts, hotel housekeeping carts, and industrial and commercial equipment.