Originally Posted by andrewwynn

I think that's a 'T10'. People will think it's hex and might round it off. It's pretty hard to strip a torx screw though.

I have a bunch of odd sizes of torx for working on computers and phones (like 7, 9 etc. Not sure if I have 11, but you can usually get a rounded torx out by going one size up and tapering the tip with a Dremel so you can hammer it into the screw.