Feature:1. DURABLE MATERIAL: Made of excellent aluminum alloy, surface oxidation treatment, durable, fine workmanship, high transmission accuracy, closed timing belt is made of strong fiber reinforced rubber, durable and elastic, has long service life, bringing you an unparalleled experience2. ACCURATE AND FIRM: Providing accurate transmission. No slippage during work, constant transmission ratio3. SUITABLE FOR DIY: Bring smooth transmission, accurate pitch, high transmission efficiency, good energy saving effect, many DIY enthusiasts are full of praise for it, and will also be your best choice4. SIMPLE STRUCTURE: Easy installation and disassembly, with a wrench, used together to make your 3D printer work easier and more convenient5. WIDE APPLICATION: As a stepper motor pulley kit, widely used in 3d printers, milling machines, gear grinding machines, drilling machines, CNC lathes, gear hobbing machines or other mechanical transmission occasionSpecification:Item Type: Synchronous WheelMaterial: Aluminum alloy, rubberTiming Belt: Length: Approx. 200mm / 7.87in, Width: Approx. 6mm / 0.24inTeeth: 20T and 60TScrew: M4.Package List:4 x Synchronous Wheel2 x Belt1 x Hex Wrench