Originally Posted by MrChad
No it's called a rear disc brake caliper tool, seriously.
Most large autopart stores will sell you one for 30bucks, I got mine from Tommy's Auto but you can also get one at Sears.
It's a multi-sides square tool and it works with a socket wrench. Keeps you from slipping and tearing the boot on the caliper.
That's pretty cool. I don't change enough brakes for it to be worth it, but it's good to know that such a tool exists.