You needs a timing pulley when using a belt to drive some axis of the 3D printer. This timing pulley is made of aluminum alloy, a good 3d printer accessories for you to choose. Features Aluminum Alloy material, durable to use. This timing pulley fits for GT2 6mm belt width 3D printer. Gives better smoothness and accuracy of positioning, resulting in better printing quality. Widely used in milling machine, 3D printer, CNC engine lathe, and other industries. Specifications Brand Anet Material Aluminum alloy Quantity 4pc Gear Teeth 16 Height 15mm Bore Diameter 5mm Flange Outer Diameter 13mm Teeth Outer Diameter 9.5mm Package Weight 200g Package Size (L x W x H) 100 x 80 x 70 mm Package Contents 4 x Timing Pulley for 3D Printer