Product review (4 stars): Works great when not encrusted with ice!
Works well, easy to use. Need to make sure the sensors are not too far from the base station if you're using them to measure cold temperatures. My wife manages an ice cream store and I set this up for her so she gets alerts when a freezer temp gets too high. It has paid for itself several times over by now. My wife just sent me the attached photo of one that got shoved too near a drippy coil. I suspect it is not as effective that way, but it does make its own nice little ice angel. Be sure to use lithium batteries if you use it in extreme cold, because the others just won't survive very long.