The timing belt kit is designed specifically for linear motion and precision, high positioning accuracy 20-tooth timing pulley minimizes the risk of belt slippage The timing belt is made of premium rubber, more and flexible Comes with a 5m timing belt, an 8-piece timing pulley, as well as a hex wrench Popular choices for Reprap, Prusa, MendelMax, 3D printer At least six teeth in contact with the pulley at any given time. This will reduce the possibility of slipping. The pulley and belt are used together, and the profile with rounded teeth, which ensures that the belt tooth is smoothly and accurately in the pulley groove. The anti-reverse timing belt pulley with 20 teeth is one of the best choices for 3D printer construction. COLOR: Black and Silver Timing Belt: Material: Rubber Length: 5m Width: 6mm Pitch: 2mm Color: Black Timing Pulley: Material: Aluminum Diameter: 16mm Hole: 5mm Teeth: 20 Package Included: 2 * 5m Timing Belt 16 * 20T Timing Pulley 2 * Hex Key Only the above package