General Description This grooved pulley is ideal for use in doors and windows, allowing mechanical equipment to be tracked and driven. Each set includes four pulleys, perfect for various DIY projects. Technical Specifications Model: 0840UU Type: U-groove Material: Metal and plastic Color: Black Inner diameter: 8 mm Outer diameter: 40 mm Thickness: 20.7 mm Quantity: 4 pieces Weight: Approx. 109 g Compatibility and Accessories This pulley is compatible with various door and window systems equipped with U-tracks. It can be used in conjunction with bearings and other guide accessories. Installation To install the pulley, follow these steps: Remove the old pulley if necessary. Insert the new pulley into the U-track. Ensure the pulley is correctly aligned. Test the movement to verify smooth operation. Use This pulley is used to facilitate the movement of doors and windows, providing an efficient solution for sliding systems. Thanks to its design, it allows for quiet and smooth operation.