Torx Size for Changing brakes....

I have an '04 Chevy Suburban that I am needing to change the brake pads on. I went to do it the other day and found that it has a Torx head bolt holding the caliper on. I don't run across Torx heads much and I only do the simple things, oil, brake pads etc. on my vehicles. I really don't want to spend $20 on a Torx head set only to find that the 7pcs don't include the right size, plus I would rather just buy the one that I need to do this job specifically.
 
So the question is what size of Torx head wrench do I need to get to fit this? Does anyone know?
 
Thanks

It`s a 55 If I recall.

T55 is the right torx bit for the brake caliper.[IMG]http://i14.tinypic.com/5y8whhz.jpg[/IMG] flawdafred