Worth having in the saddle bag.

[RickJ]

Slick piece of engineering, but I've never experienced the need for such an item.

Anyone ever broken a valve stem on the road?

yup! not broken off, but leak at base of stem. wondered why I had 10lbs pressure!
[edit] you did say "on the road" it happened there, but I didn't catch it till at home. I had to remove the wheel,to replace the stem, and figured what the hell, and got a tire too- could have waited another 1K or more if I had had that nifty thingy.