I'm partial to my Byrdwrench, even though the one I have looks like a "good enough" Chinese early production model (which it probably is). I have often needed a small adjustable wrench in everyday carry, and I have carried small crescent wrenches on my keychain, which is less than ideal to say the least.

The one I own has a coarse round metal file, which is a better compliment to the wrench than the diamond file I have seen on other variants of this tool. The big drawback to the round file is that it doesn't mount to the tool in a usable way. I talked to a machinist friend of mine, and he thinks it would be difficult and probably impractical to engineer some sort of threaded mount for it. If anyone knows whether this has been done successfully, please let me know.
I also have a CRKT Guppie, which is similar but much lighter duty. Basically a conversation piece.
