Why need a torque multiplier? A torque multiplier is a tool that is commonly used in the automotive industry to increase the torque output of a wrench. This torque multiplier lug nut wrench is particularly useful when working with large, stubborn, or corroded bolts or nuts that require a significant amount of force to loosen or tighten. In the case of cars, torque multipliers are commonly used for a variety of applications such as changing tires, adjusting suspension components, and working on engine components. Without a heavy-duty torque multiplier set, it can be very difficult or even impossible to apply the necessary torque to these components, which can lead to stripped bolts, damaged components, or even injury to the mechanic.