These are ball casters rollers using carbon steel materials, sturdy and for long time to use. Suitable for processing machinery, furniture, toys, etc, have good using effect. Compact size and light weight, easy to use, bring you convenience, easy to install and maintain. The ball bearing design ensures smooth and efficient operation. Features -Color:Silver -Material:Carbon steel -Size:5.00X3.50X2.50cm/1.97X1.38X0.98in - Made of sturdy carbon steel material, our ball rollers can move and rotate safely. - Widely used in home appliance, transmission system, wooden case, transmission furniture and so on. - Strong stability: adopting ball bearing transmission design, smooth operation and low noise. - The bearing units are strong and , good wear resistance and not easy to wear out. - Good craftsmanship, featuring smooth and rounded corners, stable functions. Package list: 6 transfer bearings