Bearing Pulley, 4pcs 0840UU Ball Bearing, U Groove Pulley, Wheel Sealed Groove Bearings with Groove, for Linear Motion System on Rail (8x40x20.7mm)

The U groove pulley is made of high quality material that can ensure long-term service. High precision, maintenance-free and long service life. Internal lubricating grease, smooth operation, good mute effect. U-shaped groove design, smooth surface reducing friction. This grooved pulley is widely used in doors and windows to track and guide mechanical equipment. There are total 4 pieces of pulleys in a set that many use for many projects. Stable and smooth operation, good mute effect, convenient and durable.