A world first! When the set torque is achieved, it automatically marks evidence of proper tightening on the heads of small screws and bolts. It determines whether tightening has been missed by detecting the presence or absence of marks, at the end of the manufacturing process and after shipping. MNTD series Error-proofing (Pokayoke) torque drivers mark small screws and bolts after tightening, as a human tightening error countermeasure.