Three-ohm 12V coil features a closed-core design for greater efficiency Produces far greater energy in a small package than other popular high-performance coils Can be used with any Compu-Fire ignition system or any ignition that calls for a 3-ohm coil (except Dyna S and points-type ignitions) Made in the U.S.A. Not for Twin Cam applications.. COMPU-FIRE COIL DUAL FIRE