"Wrench will fit over all lengths Big Twin transmission mainshafts so that you can properly torque the sprocket locknut to 100-120 ft. lbs. Use any 1/2"" drive ratchet, impact or torque wrench. Special features include left hand threaded collar that screws on end of mainshaft and pilots tool. Prevents damaging the sprocket locknut. Will fit all stock sprocket lock nuts and super nut. Fits all Big Twins 1936-later."