The E3 HEI Coil in Cap features a superior design that works with aftermarket performance 4-pin modules and high performance electronic controls. The coil's resistance and inductance values have been optimized to match the high amperage dwell circuits of performance ignition modules for faster charging and full coil saturation at higher RPM levels, translating into better performance. High temperature epoxy resists shock and vibration while providing excellent thermal conductivity ensuring long service life.