Error proofing by design flattened case prevents side loading. Flattened case provides support for click mechanism so the wrench is easier to calibrate and it holds calibration longer. Error proofing by guidance creates excellent tactile and audible pulse when the preset torque is achieved. - Cushioned comfort grip plus lightweight for excellent ergonomics. Slide pin ratchet provides excellent strength and durability. The torque is preset and locked in with a special tool. Torque can be set using any unit of measurement.