TEC1-12706 is a ThermoelectricCooler that utilizes the thermoelectric effect for cooling. The thermoelectric effect is where an electric current is generated when two different metals pass through a thermal conduction between them.There are two pieces of metal inside the TEC1-12706, and when one of them receives heat, an electric current is generated in the other piece of metal. This allows the heat to be transferred to the other metal piece, realizing the cooling effect.