Good Return Service, Good Unit
I had to return one shipment since the unit did not work - it made no sound when the batteries were inserted and the contact was opened. That was even after replacing the package batteries with others.  However, there was no problem returning it, and when I bought a replacement (apparently one can't just do an exchange, but it's free shipping in both directions), it works perfectly. The clip is very tight and can be hard to snap closed or open, but you can replace it with a standard office ID lanyard clip (which I did) that still grips well but is easier to use.
Rating: 4 stars