The ES-645L1 is a lever start screwdriver with a slip/cushion type clutch. The slip/cushion clutch slips once the pre-set torque is reached. This feels like a slight release of pressure on the bit of the screwdriver to the operator. The torque setting is set by adjusting the stepless torque adjuster at the top of the screwdriver. Common usages for this screwdriver are tapping screws and applications with less stringent torque control requirements.