Power take–offs (PTOs) are mechanical gearboxes that attach to apertures provided on truck transmissions and are used to transfer the power of the vehicle engine to auxiliary components, most commonly a hydraulic pump.

Hydraulic P.T.O. gear boxes are used to change either the rotation speed, the torque or the rotational axis in combination with one of the mentioned factors in a hydraulic system. P.T.O. gear boxes are also often used to operate hydraulic gear pumps.