Perfect ignition timing once and for all. Self-contained ignition system features Hall Effect magnetic sensors, which are not sensitive to rpm changes or affected by dirt and oil. Improves overall performance by changing the timing less than three degrees, extends plug life, eliminates the use of points and condensers; can be easily installed. Used and endorsed by many championship racers. Made in the U.S.A. NOTE: An advance weight mechanism is required. NOTE: Not recommended for use with OEM coils.