<p>The hydraulic wrench or screw fastener has a drive part (10) and a function part (11) with a housing (14). The housing contains a ratchet arm driven by the drive part. The ratchet arm drives a shaft (17) running through the housing. The shaft has a pick up and a measuring section which determines the torque. The measuring section is arranged at least partly in the part of the shaft surrounded by the housing.</p>
