A torque wrench is a special tool that allows users to apply a precisely defined torque (force) to a bolt or nut. This precision is key to ensuring that bolts and nuts are tightened correctly without damaging them or under-tightening them, which could lead to the failure of mechanical components. Torque wrenches are essential in situations where it is important to maintain specific torques, such as engine assembly, machine assembly or in the aerospace industry where incorrect tightening can cause serious problems.