Widely used in home appliances, industrial. Low noise and high speed electric motors, construction machinery, automotive components, pumps, and machinery. Smooth moving, low friction, high rigidity and long life. Economical, easy to maintain replace. Productname: Open Linear Motion Bearing Slide Unit Model: SBR12UU Inner diameter: 12mm/0.47 inch Length: 39mm/1.54 inch Width: 41mm/1.61 inch Heigth: 28mm/1.1 inch Color: silver Material: Aluminum base alloy + bearing steel Package Contents: 4 * SBR12UU Bearing Block Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.