High Quality Material: Made of high quality Brass which is corrosion and rust proof, highly durable. These Brass Pulley Gears are known for their stable use with great bearing capacity. They improve your 3D printer's effeciency. Easy to Use: Super easy to replace your old or worn Driver Gear Pulley. Use the Allen Key Wrench that comes with the set to unscrew the Allen Head Screws on the old Pulley. When the screw is loose, remove the Pulley and place the new Pulley. Tighten the screw . Compatible with Creality 3D Printer Ender 3 V2/ Ender 3/ Ender 3 Pro/Ender 5/ CR-10/10S 20/20 Pro and most other 3D Printers Set Contains: 5x Brass 40 Teeth Pulley Driver Gear; 1x Allen Hex Key Wrench High quality product by MMOBIEL: Each part is tested before shipment. Item in Stock.