The sensible thing would be to remove the wheel and look . Test some wrenches on it, see what works. -After all you are changing or repairing the most important part of your car. Why take someone else's opinion .
3/8 in.
It's 12 mm bolts, not Allen key.
That is a 3/8 Allen.
7mm Allen wrench
That is a 3/8 Allen.
Cavaliers from '94 to '03 all take 3/8 Allen key on calipers.
You need 3/8 Allen key.
I believe that will be a 7mm Allen key.
7mm
3/8" Allen wrench.
3/8"
3/8" Allen wrench