Designed for a wide variety of cars with 12mm jam nut valve adjustment screws. This two in one tool features a window in its socket so the technician can see the position of the screwdriver blade holding the adjustment screw as the jam nut is tightened. This visual contact in addition to the feel of holding the screwdriver allows for quicker valve adjustment times as the technician can hold the adjustment screw exactly where he wants it. The unique handle pivots from one side to the other, so the window is always visible. Made from heat treated chrome vanadium steel this tool comes with a soft grip handle