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, and eliminates the use of points and condensers Can be easily installed Used and endorsed by many championship racers Made in the U.S.A. Operation with the Dyna S ignition system requires the use of an aftermarket 5 ohm coil such as part # DC7-1 or a stock points coil from early Shovelheads. Not recommended for operation with OEM coils.. IGNITION DYNA-S 70-99 H-D