MSD developed a replacement coil that incorporates improved windings and material to increase the output of the coil. Also, when other modifications are being added, you can rely on the Blaster Coil to recover quicker through high rpm with a powerful spark to promote combustion. These late model Jeep coils are designed as direct replacements for the 4.0L engine. It is one complete coil pack, so it mounts in the factory location and simply plugs into the factory connector. If you are looking for an upgrade from stock, MSD Blaster ignition coils will provide the power, reliability, and quality you've come to expect from the MSD name.