The 127-15 (127 interface, 15 amps) is a workhorse. It features thinner alumina plates (better thermal conductivity) than the more common TEC1-12705 and 12706, fatter wires, and can be run at up to 134 watts with sufficient cooling. Recommend running at 100 watts per module or below for excellent performance and longevity. While you can push a 12705 to 80 watts or more, all you’ll get is heat. The 12715 is happy at 100-180 watts with appropriate cooling.