Adjustable Timing Control The Adjustable Timing Control Puts You In Control Of Your Timing From The Driver'S Seat MSD IgnitionThe control knob mounts to the dash board for easy and accurate timing adjustments up to 15 Degree. The Control can be used on 4, 6 and 8 cylinder engines and must be used with an MSD Ignition Control. A dash mounted control knob allows you to adjust the ignition timing to compensate for changes in altitude, low octane gas, or heavy loads. For cars driven every day but raced occasionally on the weekends, this control is perfect. Increased fuel mileage