ITEM NAME:W1 Deep V Groove W-rail Guide Line Track Pulley Rollers Ball Bearings Steel I9C2 W1 Deep V Groove W-rail Guide Line Track Pulley Rollers Ball Bearings Steel I9C2 Model: W1 Material: Bearing steel Bore Dia: 4.763mm Outer Dia: 19.56mm Total Height: 7.87mm Colour: Silver Smooth moving,low friction,high performance and long life. Widely used in various of machinery,such as home appliances,industrial,construction machinery,automotive components,ect. Package Included: 1 x Line Track Rollers Bearing 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..Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. Material: Bearing steel. Smooth moving,low friction,high performance and long life.