Double Side Rubber Seal Linear Motion Ball Bearing Bushing.Great for linear motion on 3D printer, cnc, and other applications.These ball bearing with two rubber dust sealed to prevent ingress of dirt, water and foreign matter.Smooth moving, low friction, high rigidity and long life.Economical, easy to maintain replace.Product Name: Linear BearingMaterial: Bearing steelColor: Silver ToneWeight: 337gModel: LM20UUOutside Diameter: 32mmInside Diameter: 20mmLength: 42mmPackage Contents:4 pcs x Linear BearingOnly the above package content, other products are not included.Note: Light 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.