Thermaltake TWV480 Total Watts Viewer Power Supply
 

Leave it to Thermaltake to come up with some twist to a mundane device like a power
supply. Enter the TWV480 Total Watts Viewer, part of the Thermaltake Pure Power Series... Included
is a 5-1/4” bay device that monitors the total wattage your system is using and allows you to
manually control one of the fans in the supply and the auxiliary fan...

http://www.bigbruin.com/reviews/totalwattsviewer/