A spark fan. What else can you call it? A spark plug with a real rotating propeller on the central electrode ...
You'll find the strangest things in that classic spark plug world. This spark plug was a fluke, but we have already met a collector there heal know a lot about it.
But if old spark plugs are collection items, what else can be collected? Piston? Distributor caps? Door handles? Rear-view mirrors?
If you have such a special collection, then you can report!
What haven't we all had? Split fire, U groove, Brisk, two, three and four ground electrodes. All so good that no more gas is needed and he is already running on his spark 😉
The best are iridium spark plugs, very thin central electrode, at pointed points less voltage is needed to get a spark (ionizes easier) and the thin electrode also makes the mixture flush better.