The Control Products basic freeze alarm is a great value and easy to program. I tested it by placing it outside in December (I live in Minnesota) - but could have put it in the freezer, too. It takes almost an hour for the device to acclimate to the cold, so be patient. Once it got colder than the low temp setting I established, it called my cellphone. It also has a feature that will call my cellphone every 2 hours, just in case I somehow miss the first call. This is a great little device for a very reasonable cost!