Mine is the one in the engine. That's one reason I bought it. I didn't want a separate box. Frankly, until the self-contained Trispark came out, I had no intention of "going back" to E-ignition. The Boyer that was on the bike when I bought it was terrible - kickbacks even with timing set correctly, weak spark in general, non-optimum advance curve for the engine. I removed it and installed the original mechanical ignition. The points/AAU worked perfectly with a better advance curve for the engine. The added maintenance, was, IMO, of no consequence at all in the scheme of routine maintenance. But when the TriSpark showed up I decided to try it since it pretty much duplicated the OEM advance curve. If the Trispark ever fails, I'll go back to the points/AAU without a second thought.