Great for Science Fair projects or for school science labs to demonstrate the Peltier effect. Also used for humidors and other self-contained heating/cooling needs. These are complete Peltier assemblies, with module, heat sinks, and fans - one for each side. Capable of modifying a closed system temperature by 40-60 degrees. Great for cooling electronic equipment, or providing a heat source. Can also generate electricity. New units, 12VDC, removed from Igloo thermoelectric coolers (that sell for $90 or higher). Price is only $39 each, plus shipping. Multiple units are available - will entertain offer for all 71.