Daytona Twin Tec Ignition Kit For Harley Ignition system has two advance curve families with adjustable advance curves to accommodate stock to wild engine modifications. Kit has four rotary switches for adjusting timing and single-dual fire rpm limit digitally set rpm limit (in 100 rpm steps). Features: Kit includes ignition module, 8.5mm spark plug wires, single-fire coil and instructions Four rotary switches for adjusting timing and single-dual fire rpm limit digitally set rpm limit (in 100 rpm steps) Selectable single or dual-fire mode Selectable multi-spark mode for quick starting and smooth cruising Coil outputs protected against short circuits Optional USB interface kit and software (programs available on website www.daytona-twintec.com/index.html) available for programming custom curves (PC-link cable must be purchased separately) Requires the use of Ignition Rotor 383-497 Uses the tachometer wire for the USB interface and comes with a connector Made in USA