pulleys are spinning formed bysheet metal that is the most advanced structure. due to uniformityand nice balance, it is unnecessary to deal with balance. besides,because the material line will not be cut off (non-cuttingprocessing), the surface becomes hardened and the densityincreased, to improve the surface of wheel’s strength and hardness.the high dimensional accuracy let the slip of belts and wheelsbecome small, and the use of belts become lasting. compared withspinning pulley and cast iron pulley, there are many advantageslike light structure, saving materials, inexpensive, etc, which isa new nice energy-saving product.