Plug size

OK, I feel like a real novice asking this question . …but here goes…

What size is the sparkplug that goes into the S1 engine. Is it 13/16" or 5/8". Is the diammeter 10mm?

Reason: Buying a T-bar plug wrench online and have ABSOLUTELY no idea of plug sizes

Cheers chaps

16mm (5/8") socket will have 'em out in a trice

OK, I feel like a real novice asking this question

You shouldn’t, it’s pretty much why we’re all here.

Ian