Impact wrenches can't tell you with any accuracy how much torque is being applied. RAD Torque Guns are calibrated and have model options with accuracy ratings from +/- 1% - 5% so you can be assured you have reached proper torque without fail. . Impact wrenches are aptly named...they have a tremendous impact on the user. RAD Torque Guns provide easy operation regardless of torque load with no impact on the user.