And I went into a panic reading the early posts and didn't even realize somebody has already posted the 12mm 12 point bit. Sorry for the stridency -- I didn't want you to ruin those bolts. They can be a real pain sometimes NOT stripped, lol.
For instance, when you are lying under a propped up junkyard vehicle trying to take the bolts out with inadequate room. That's the most fun most folks have with them, lol.