Feature:1. Made of carbon steel, and to heavy loads, effectively resist oxidation, rust and has long service life.2. Suitable for most nail drill pen, universal fitment makes it suitable for all electric nail drill model.3. Both sides of the bearing are protected to from entering, wonderful replacement accessory.4. Easy and convenient for installation and disassemble, reliable and to use, practical accessory.5. There are 6 different models electric nail drill machine bearing types available, you can choose according to your demands.Spec:Item Type: Electric Nail Drill Machine BearingMaterial: Carbon Steel Raceway Type: Spherical racewayScope of Application: Universal nail drill pen Size Inner Diameter Outer Diameter Thickness 830 3mm / 0.1in 8mm / 0.3in 4mm / 0.2in 940 4mm / 0.2in 9mm / 0.4in 4mm / 0.2in 1030 3mm / 0.1in 10mm / 0.4in 4mm / 0.2in 1040 4mm / 0.2in 10mm / 0.4in 4mm / 0.2in 1260 6mm / 0.2in 12mm / 0.5in 4mm / 0.2in 1480 8mm / 0.3in 14mm / 0.6in 4mm / 0.2in Package List:1 x Electric Nail Drill Machine Bearing