I loathe anything on my wrists. A $25 timex from WallyWorld, and a length of 10 pound test cotton twine to hold it as a pendant. I have to replace the twine every 6 months or so, but it is light enough that if gets hung up on something, a sharp jerk of my head will snap it easily enough. Just remember to turn your head so that the impact is onyour jaw, not your adam's apple. <img src="/images/graemlins/smile.gif" alt="" /> More likely, I'll just snap it with my hands, and I've actually done that a few time accidently.

If you wanted a really spiffy break away, I suppose you could use a bit of heat shrink.