I recently acquired a precision II probe when I perchased my new CZ-3D.
Haven't used it yet... not too sure if it would help much, as it only picks up a signal from a coin about 1" away...
I figure by the time I'm a inch away from a target, it won't be long before I find it...
I would imagine one of the better probes would be great to use, but as for this one, it's size, and no better than it works,, I just leave it in the box...
I should take it out for a field test,,, maybe with the halo effect it will do a better job of getting a signal.