【HIGH QUALITY MATERIAL】The 5 x 2 inch wide thermoplastic rubber wheels are bonded with an extremely high quality non-marking gray thermoplastic engineered rubber tread. These wheels are softer than the standard urethane wheels you'd normally use. These are designed to roll over debris, gaps, cracks, obstacles with ease. Can be used in many applications such as food service, hospital, laboratory, and many institutional applications and industries. 【SMOOTH & NON-MARKING】High-quality ball bearings are selected to extend the service life of the bearings. Made of plastic rubber material, these casters are non-marking, quiet, shock-absorbing, vibration-absorbing, and can effectively protect equipment and floors as well as many floor surfaces. 【WIDELY USED HEAVY DUTY CASTERS】400 lbs load per caster. Total load on all four wheels is 1600 lbs. Heavy-duty casters can be used in industrial and residential applications such as carts, cabinets, bookshelves, shopping carts, display exhibit equipment, carts, mobile workstations, furniture and more. 【STURDY AND DURABLE】The heavy-duty caster set is made of high-quality steel shell, thickened top plate. Top plate dimensions: 4x 4-1/2, total height: 6-1/2 . This sturdy construction makes it a heavy-duty caster for a wide range of applications. 【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