Help!!!!!

Not really a technical question - I'm trying to work out what type/size nut I need for the original indicators on a Daytona 955i as it doesn't seem to be metric. Have tried looking at various parts lists but no joy

 

Errr no wasn't checking scientifically, just trying a few in the local hardware store. It's a finer pitch than the aftermarket ones currently fitted.....

 

Thanks for all the replies, think I can find what's needed now.....