Idler gear is the gear positioned between the input and output shafts (between the drive gear and the driven gear). It can be used, for instance, to alter the output shaft's direction of rotation or to bridge a significant gap between the input and output shafts without changing the speed ratio. In addition to this, the said product is used in gear trains to ensure that the output shaft rotates in the desired direction. Idle gear should be noticed that both the driver and driven or follower gears move similarly when the number of intermediate gears is odd.