We have an expert on camping stoves, a good number of HAMs, sailors, etc. Any compass guys?

I am looking for a keychain compass. Small would be nice. Keychains get dropped, so the ability to withstand shock would be nice. I don't expect to go into the wilderness and read topographical maps with it. Most of the time I'll be using the keychain compass in an urban setting, or while driving.

I can't tell whether there is any difference amongst the items I found online. The technology seems pretty simple to me, but perhaps there are fine differences that only real experts can tell.

I had a keychain compass with thermometer (Suunto), but after two or three years it stopped working so well. I also have a compass app on my Android, but it failed me this afternoon. The digital compass on my watch (Highgear) has a 20 second limit, and I'm still not sure how much I trust it.

Thanks!

Just had a lunch of BBQ ribs. Man, am I full and loaded with cholesterol!