Listing is for a set of four (4) Service Caster Series #30 swivel casters with 4" diameter by 2" wide v-groove semi steel wheel and maintenance free precision ball wheel bearings with top lock brakes and bolt on swivel locks capable of supporting a total weight of 3,200 lbs. (800 lbs. per caster). When searching for a reliable and durable solution for heavy duty projects, consider Service Caster?s Series 30 top plate semi steel cast iron v-groove wheel casters. The Service Caster Series #30 v-groove wheel is designed to roll on 45 degree angled track, and also has a flat face suitable for non-tracked use. The semi-steel cast iron wheel is built to withstand high capacity, heavy loads up to 1250lbs and in temperatures up to 600?F. An economic choice over steel, semi-steel wheels are abrasion resistant and rugged. Finely crafted with double ball bearing heat treated raceways, these versatile casters are ideal for a wide range of applications specific to high capacity tracked workflows, but also for dollies, platform trucks, warehouse carts and freight terminals. Or ensure a smooth and secure ride for 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.