I recently acquired a McMurdo PLB FastFind 210. I'm happy to report that, at this point in time, I don't have any idea how well it works.

As I recall, however, reading through the manual, I was struck by the somewhat mysterious flashing responses in response to this or that test mode, activation, whatever--that signal the functional status of the unit. (Again, this is to the best of my recollection now.) It reminded me of the first Steri-Pen UV water purifying unit (paraphrasing now: "If the unit is sterilizing, it will turn green and blink twice. If not it will turn purple and buzz three times. If it's not yet completed it's cycle it will ring once and then spin around and hop up and down.").

The newer Steri unit now has a smiley face on it to show it's doing what it's supposed to. I think I would like a smiley-face on my PLB to comfort me that it's working when I'm laying next to the big boulder I just fell of off and broke my "axe".