Ultra reliable dual fire electronic ignition system 1970 thru 1984 Shovelhead, 1984 thru 1999 Evolution Big Twin and 1978 thru 1997 Sportsters. The ignition includes a special trigger rotor for use with the stock mechanical advance mechanism. The VT-i ignition features a precise digitally set RPM limiter (200 RPM steps from 5.200 to 7.000 RPM), a status LED for easy static timing, electronic dwell control for maximum ignition energy at high RPM and reduced current draw at low RPM. The VT-i is compatible with most original equipment and aftermarket dual fire ignition coils with 3 to 5 ohms primary resistance. Apart from the very easy installation with just two wires to hook up to the coil one of the biggest advantages of this ignition is that it operates down to below 6 volts for reliable starting under all conditions, including kick start.