Material: PA66Bearing material: bearing steelWeight: About 16gSpecifications: Inner hole=8mm, outer diameter=32mm, thickness=12mmColor: BlackPackage included: 1pcs Bearing pulleyProduct features:1. These bearing wheel rollers are fabricated from POM and nylon materials, offering splendid existence resistance and put on resistance. POM is a kind of engineering plastic with high strength, high stiffness and good sliding property, while nylon has nice influence resistance and heat resistance.2. Because these wheels are designed with pointed rolling bearings, they provide the lowest friction and most efficiency when sliding and shifting objects. This can enormously save calories and effort.3. These bearing wheel rollers are uncomplicated and intuitive to use, making them splendid for any equipment and mechanical device that needs comfortable movement. They would be easily suited for the lowest of products or objects to provide easy movement.4. Due to their durability and sliding properties, those wheels are superb for a wide range of purposes reminiscent of warehouse logistics, business equipment, furniture, strength tools, etc. They can work reliably in a wide range of environmental conditions.Notes:1.Please enable 1-2cm variations because of manual measurement, thanks.2.Please understand due to the light irradiation or computer reveal difference, so I can not guarantee images and real coloration is the same.