1、Great Replacement Parts: The set contains 2 piece linear motion bearing for you to use, can directly replace old or broken ones. 2、Excellent Bearing Steel Material: The bearing adopts excellent bearing steel material, heat treatment processed, has high rigidity. 3、High Performance: This linear motion bearing can move smoothly with low friction, providing precise linear motion. 4、Standard Size: The bearings are manufactured by professional craftsmanship, with standard size, easy to install. 5、Wide Application: The long linear motion bearing can be widely used in 3D printers, various of CNC machines. 2 x Long Linear Motion Bearing Item Type: Long Linear Motion BearingMaterial: Bearing SteelModel: LM12LUUInner Diameter: Approx.12mm/ 0.5inOuter Diameter: Approx.21mm/ 0.8inLength: Approx.57mm/ 2.2in