I keep this in my flat repair pouch:
It has a steel core and is wrapped/coated in hard black plastic. It doubles as both a 15mm wrench for rear axle nuts and a nice tire lever. It is wider than my cheapie plastic tire levers and performs basically the same function, but it is unbreakable. The one thing it won't do is hook onto a spoke for the first step in tire removal (I keep 2 cheapie plastic levers with spoke hook ends too, for performing the first part of removing the tire). The plastic coating means no scratches on rim. As a wrench, it is shorter than my 15mm regular steel wrenches, but I like the angle when wrenching - it seems designed just for this task. So, it serves two purposes in the flat kit.
I've only had to use it once, but I like it and consider it a lifetime tool, like my Ortlieb panniers. It's one of those tools that is expensive, but perfect for my use and durable.
PDW 3wrencho:
http://www.ridepdw.com/goods/tools/3...2%84%A2-coated