A torque wrench is a tool used to apply a specific torque to a fastener such as a nut or bolt.
A torque wrench is used where the tightness of bolts is crucial such as in case of gasket installation or suspension components. It allows the mechanic to set the torque applied to the fastener so it can be matched to the specifications for a particular application.
This permits proper tension and loading of all parts. A torque wrench uses torque as a proxy for bolt tension.
Use a torque wrench set to prevent common over-tightening problems and avoid expensive fixes later.