HIGH QUALITY: Made of high quality , durable with the resistance of wear and collision. FEATURE: It is characterized by small frictional resistance and high rotational speed and can be used on mechanical parts that are subjected to loads or axial loads, such as machine tool, electronic equipment, . GOOD DESIGN: Exquisite design, two sides metal sealed ball , with good dustproof effect. Built-in precise Mini provides running and long service life. Great products for standard and DIY. Perfect for use: Wood,tools, and so on. color:Silver : steel size:. 16 x 31 x 10mm Package Contents: 10 x Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.