Daytona Twin Tec External Module Ignition Kit For Harley Daytona Twin Tec External Module Ignition Kit is two advance curve families with adjustable advance curves to accommodate stock to wild engine modifications. Unit has four rotary switches for adjusting timing, single/dual fire, rpm limit and two LED indicator lights. Features: Kits include ignition module, single-fire coil, 8.5mm spark plug wires and instructions 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 PC-link cable and software available (programs available on website www.daytona-twintec.com/index.html) for programming custom curves (PC-link cable must be purchased separately) Use the tachometer wire for the PC-link and comes with a connector