1Aluminum Alloy Timing Pulley: Made of premium aluminum alloy, appearance oxidation treatment, our timing pulleys are durable, with fine workmanship and high transmission accuracy. 2With Rubber Timing Belt: The timing belt is made of excellent fiber reinforced rubber, which is durable and elastic for a long service life. 3Accurate Operation: The pulleys and belts have no slippage when working, and has constant transmission ratio. 4Easy to Install: Comes with simple structure and included wrench, the installation can be quickly completed in few steps. 5Wide Application: These timing pulleys are widely used in 3D printers, milling machines, gear grinding machines, drilling machines, CNC lathes, gear hobbing machines or other mechanical transmission scenarios. Item Type: Timing Pulley Set Material: Aluminum Alloy, Rubber Timing Belt: Length: Approx. 1220mm or 48in Width: Approx. 6mm or 0.2in Number of Teeth: 20, 60T Screw: M4 4 x Timing Pulley 2 x Timing Belt 1 x Hex key