Item Type: Linear Motion Bearing_x000D_Model: LMK30UU_x000D_Material: Bearing Steel_x000D_Inner Diameter: Approx. 30mm / 1.2in_x000D_Diameter: Approx. 45mm / 1.8in_x000D_Thickness: Approx. 64mm / 2.5in 1FOR LINEAR SYSTEM: Linear bearing is used in conjunction with quenched linear drive shaft for linear motion system, with low friction resistance and high accuracy. 2LOW LOAD: Since the bearing ball is in point contact with the shaft, the load is small, and the steel ball rotates with minimal frictional resistance. 3STANDARD SIZE: Including 2pcs square flange linear bearing, inner diameter is 30mm, diameter is 45mm, thickness is 64mm, standard in size, easy to use. 4BEARING STEEL: Using excellent bearing steel, which has high hardness, high contact fatigue strength, rust resistance and wear resistance, long service life. 5WIDE APPLICATION: Used in electronic equipment, tensile testing machines, digital 3D coordinate measuring equipment and multiple axes machine tools, etc.2 x Linear Motion Bearing