There are two types of torque screwdrivers: signal-type and direct reading models. Click type torque screwdrivers are used primarily for tightening. When the set torque is achieved, rotary slip prevents over-torque, and the hand feels a release of tension, indicating tightened-to-completion. Direct reading torque screwdrivers are used primarily for measuring and inspection. They display numerical measurement values. We also supply Pokayoke (error-proof) torque screwdrivers designed to prevent human tightening errors.