Abstract: An impulse wrench comprises a pneumatic rotation motor (12), a hydraulic torque impulse generator (13) provided with an impulse magnitude responsive actuator (17), a linear movement responsive electric signal producing device (25) located at the rear end of the motor (12), a movement transferring push rod (21) extending through an axial bore (22) in the motor rotor (16) and interconnecting the actuator (17) and the signal producing device (25), an electrically activated motive air shut-off valve (31) disposed concentrically with the signal producing device (25), and an external process controlling and monitoring unit (40) connected to the signal producing device (25) and the shut-off valve (31) and arranged to compute and compare received signals with predetermined values and to initiate shut-off of the power supply (31) as a desired tightening condition is reached.