Melvin at MBS Model Supply has those. At least I think he still carries them. I have a spare one and one I use considerably. Even have a cord made up with Alligator clips on one end. Have them staggered so they don't get together and short out. I do not like the head lock thingy. The alligator clips are easy to pull off once engine is started. Th Magnum clips are easy to get off also during a pit stop in racing.