Suitalbe for CNC machine electronic equipment,drive shaft, and etc.Colour:silverMaterial:MetalSize:Inner diamter: 16mm ( LM16UUOP)Package Contents:4 x SBR16UU SBR Linear Ball Bearing Slide BlockOnly 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.