Product review (5 stars): I Nominate This for Gadget, Product of the Year
This meter is so simple I can even make it work with ease, too.  The best of all is that it works without one wire or even 5 Watt connector.  It has to go down in the archives as The est All Manuel Device of the Year and probably Decade.  The most difficult part of "constructing" the device is getting it to stand up.  I cheated, though.  I froze the water in the barely used outside fridge.

With our present configuration of 2 refrigerators we have had 3 separate occasions of multiple days of no frozen air:  2 snow days and 2 other times of multiple days of outages.  Each time could have generate a reading that would qualify as a food failure.  The ball floating to the bottom is not always 100%.  Judy brought me a 6 pack of center cut pork chops and asked me to give it a sniff check.  The meat had the right pork color and an odor not fit for your worst enemy.  So, we use that old saying, "If it stinks and drops, chunk it!"