Product FeaturesProduct Name: Linear Bearing; Model: LMK12UU; Material: Metal, RubberInner Diameter: 12mm/0.47"; Outer Diameter: 21mm/0.82"; Length: 30mm/1.2"Size: 31 x 31 x 5mm/1.2" x 1.2" x 0.2"(L*W*T); Mounting Hole Diameter (Each): 4mm/0.16"Hole Distance: 21mm/0.83" (Center to Center); Color: Silver Tone, Black; Net Weight: 55gThis universal bearing is ideal for replacing damaged ones in your devices, improving efficiency and saving energy.Widely used in industrial applications, low noise and high-speed electric motors, construction machinery, automotive components, pumps, and machinery.Ensures smooth movement, low friction, high rigidity, and long service life.Economical, easy to maintain and replace.Package Contents: 1 x Linear Bearing: Light and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowable measurement error is +/- 1-3cm.