Torque multiplier
![Epicyclic gearing can be used in a torque multiplier. The sun gear (yellow)is driven by an input torque. The planet gear carrier (green) provides the output torque, while the ring gear (red) is fixed. Note the red marks both before and after the input drive (yellow) is rotated around 170° clockwise.](/Images/godic/202502/17/Epicyclic_gear_ratios5550.png")
A torque multiplier is a tool used to provide a mechanical advantage in applying torque to turn bolts, nuts or other items designed to be actuated by application of torque, such as the actuation of valves, particularly where there are relatively high torque requirements.