A special wrench that is calibrated to measure accurate tightening forces on fasteners such as nuts and bolts. Service manuals often cite torque tightening specifications for critical applications such as wheel axles and engine components. Some applications, such as in the case of an engine cylinder head, may require being tightened down in steps and by following a specific tightening pattern – this is done to avoid warping the component. “Angle torque” is often used on critical fasteners such as connecting rod bolts and crankshaft main bearing bolts, where the fastener is torqued to a specified number, then the fastener is turned further by a certain number of degrees of rotation.