For clamps incorporating a screw or bolt, it is necessary to apply tightening torque using a torque wrench for the clamp to work correctly. The tightening torque required by a clamp in order to ensure leaktightness varies depending on the type of clamp nd the hose/coupling with which the clamp is assembled. The tightening force or torque is reduced when oil or grease is applied, thereby rendering meaningless the recommended tightening torque.