High-Material: Premium fiber reinforeced rubber, durable and flexible. Accurate transmission: without slipping at work, having a constant ratio. Smooth transmission,:a buffer, damping capacity, low noise. High transmission efficiency, energy-saving effect Specification Number of tooth: 20&60T Bore Diameter: 5mm Length of timing belt: 200mm Width of timing belt: 6mm Colour:Silver+black Material:Metal + rubber Package Contents: 2 * 2GT 20 Teeth 5mm Bore Synchronous Wheel 2 * 2GT 60 Teeth 5mm Bore Synchronous Wheel 2 * Length 200mm Width 6mm Belt 1 * Hex Key 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.