Thread size of lug nuts

I putting on new wheels and want to get chrome lug nuts. Anyone know the thread size of the lug nuts ? Believe they are a mm size ?
For a 2008 E4 Gem.

Newer GEMs with four lug wheels should have 12MM studs.

I’m pretty sure the older 2001 and up GEMs have M10’s

All GEMs newer than 2001 with four stud wheels should have M12 studs. The M10 studs were only on the early years.


Are GEM lug nuts considered ball or acorn?

Acorn are the covered lugs.