Double-sided belts have teeth equally constructed on each side of the belt, which enables them to mesh with toothed pulleys on both the inside and outside. The construction of the belts is basically the same as standard Metric belts, except that the nylon facing is also on the backing teeth, enabling full torque transmission from each side of the belt.Standard Double sided belts are available in three sizes, 5M, 8M, and 14M, all operating on standard HTD pulleys.