Does anyone know what thread this ground bolt uses?

[psdtime]

I'm trying to figure out what the thread is used on this ground stud? It's threaded on the outside and I would like to use that for any future additions since I have added so many below it. I know it looks like a nut on threaded stud, but it's actually a bolt with threads extending off of the head. This is the one closest to the battery where the battery's ground lead is attached. Thanks

Sponsored