Alltrade 648828 12-Millimeter 7-1/2-Inch Jam Nut Valve Adjustment Tool Made to be the most reliable tools in the market today Tool solutions for most all situations Built to exceed tool standards Makes adjusting valves easier Designed for engines with a 12mm jam nut and slotted valve adjusting stud Unique all-in-one design positively tightens jam nut while preventing stud movement 7-1/2" handle provides necessary torque for loosening jam nuts View window shows screwdriver blade position for easier engagement