PREMIUM MATERIAL: CWfutureparts casters feature high quality polyurethane treads with an impact resistant polypropylene core, the treads are mechanically locked to the core. The casters are resistant to most chemicals, oils, acids, greases and water. HEAVY DUTY CASTERS：Designed with strength and sturdiness in mind, these casters have a long lifespan and can handle heavy equipment and loads with ease. Each caster holds up to a maximum of 800 lbs. or 3200 lbs when purchasing a set of 4 casters. PRECISION BALL BEARING：Precision ball bearing enable high loads and higher speeds. Maintenance-free, and does not require lubrication of any type of maintenance.Use with polyurethane casters to make the casters run smoother and quieter - protect floors and create a noise-free environment. HEAVY DUTY APPLICATIONS: These casters are commonly found on large supermarket warehouse U-boat carts, hand trucks, material handling carts, and many industrial carts. WE CARE FOR YOU ：Heavy duty casters come with friendly customer service. If you have any questions, you can contact us for a solution, we will definitely provide you with a satisfactory solution. Industrial Caster