Features: 1.Inner Diameter: 8mm / 0.315in. High-quality bearings, exquisite workmanship, high precision. 2.Smooth moving, low friction, high rigidity and long life. 3.Economical, easy to maintain replace. 4.The universal ball bearings is great for you to replace the damaged ball bearings in your devices to improve them efficiency and save energy. 5.Linear bearing is widely applied to electronic equipment, packaging machinery, medical machinery, printing machinery, textile machinery, machinery, equipment, robots, tools, machinery, machine tools etc. specification: Inner Diameter: 8mm / 0.315in. High-quality bearings, exquisite workmanship, high precision. Smooth moving, low friction, high rigidity and long life. Economical, easy to maintain replace. The universal ball bearings is great for you to replace the damaged ball bearings in your devices to improve them efficiency and save energy. Linear bearing is widely applied to electronic equipment, packaging machinery, medical machinery, printing machinery, textile machinery, machinery, equipment, robots, tools, machinery, machine tools etc. s: Material: Aluminum base alloy Color: Shown as the picutures Type: Linear Ball Bearing Model: SCS8UU Inner Diameter: 8mm Length: 34.5mm/1.36" Package weight: 192g Package List: 4 x SCS8UU 8mm Linear Ball Bearing