Timing belt kit is is designed specifically for linear movement and precision, high positioning accuracy Timing pulley with 20 teeth which minimizes the risk of the belt slipping The timing belt is made of premium rubber, more durable and flexible Come with 5m GT2 timing belt , 8 pcs timing pulley, as well as an Hex wrench Popular choices for Reprap, Prusa, MendelMax,3D Printer At least six teeth in contact with the pulley at a given time. This will reduce the possibility of sliding. GT2 pulley and belt are used together, and the profile with rounded teeth, which ensures that the belt tooth smoothly and accurately into the pulley groove. Anti-backlash timing belt pulley with 20 teeth is one of the best choices for 3d printer construction. COLOR: black&silver GT2 Timing belt: Material: Rubber Length: 5m Width: 6mm Pitch: 2mm GT2 timing pulley wheel: Material: Aluminum Diameter: 16 mm Hole: 5mm Teeth: 20 Package Included: 1 * 5m GT2 timing belt 8 * 20T timing pulley 1 * Hexagon wrench Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.