Spark plugs 3 electrode type

[mike350]

I'm sure i've seen some where that by fitting a 3 electrode type spark plug to replace the NGK B7ECS ones we use can give better service. If so does any one have the NGK number for this type of plug?
Thanks in advance.

[taz200i]

I thought that the advantage of these multi-gap plugs was gained in the modern wasted spark engines i.e. they fire on the compression and the exhaust stroke.
So if your engine is not of this type then you should get a longer plug life ?????????