Lug nut spec is 12x1.5 (metric thread diameter by pitch). 21 mm is the official socket size, 13/16" will just fit too, slightly snugger. My 13/16" fits the lug nuts fine, but the first time I tried to put the locking nut socket in it was almost jamming, had to file it slightly. If you're looking for extra lug nuts you can search on Amazon, and it will verify if they fit or not. They should be the style with the captured washer up the shoulder. Gorilla is one make that's compatible, I got 4 extra, am getting tired of dealing with the locking nuts.
