S&S HI-4N Performance Ignition Module for 1970-1999 Harley-Davidson Big Twin and 1986-2003 SportsterS&S HI 4N Performance Ignition Module for 1984 1999 Harley Davidson Shovelhead, Evolution, and 1986 2003 Sportster Electronic ignition modules don't last forever, especially ones that live in the hot nose cone on Evos and Shovels. If you need a replacement, the S&S HI 4N offers adjustability OEM pattern replacements can't match. Single fire and dual fire function built into a single module All metal housing provides improved heat dissipation Ignition