My nuts are worn out! (Need new locking wheelnuts - which ones?)

Hi guys, probably due to my wheels always coming on and off via the use of an air gun, ive realised my locking wheelnuts are very close to be unusable now. Im going to grab some new ones - McGuard Ultra seem to be highly rtaed but can anyone confirm what size I need?! Im guessing theres more than one size for all the wheels/hubs out there?

thanks in advance.