HIGH QUALITY: Made of high quality bearing metal, with wear resistance and collision resistance. FEATURE: It features low frictional resistance and high rotational speed and can be used on mechanical parts subject to radial or axial loads, such as machine tools, electronic equipment, etc. GOOD: Exquisite, double-sided metal sealed ball bearing, with dustproof effect. Built-in precise mini bearing provides smooth operation and long service life. APPLICATION: Standardization size, used for machine tools, electronic equipment, pump industry, plastic machinery, motors, etc. size:15x28x7mm Material:metal color:black+silver Package Contents: 20 x Bicycle Hub Bearing Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in a little different from the real thing. The measurement allowed error is +/- 1-3 cm.