Sonic's 3/8" 10-50Nm (7-37Ft. LBS) torque wrench works in a single direction, accurately measuring the force placed on a fastener in a clock-wise motion. The handle of the wrench turns to adjust the setting, with a magnifying lens built into the handle making the numbers easy to read. A knob at the end of the handle keeps it locked during use and easily pops out for adjustment for the next fastener.