The sprocket is driven by a chain, and the model unit is generally imperial. Available in single row, double row and multiple rows. Suitable for low speed, heavy load and high temperature conditions. Compared with gears, it can be used in the center of the two axes. The gears are driven by mutual meshing. The model units are mostly metric and are expressed in modulus. The power and speed range of the drive is large. The compact structure enables a large transmission ratio, high efficiency and long service life.