When I stacked my AMS units, it didn't take long for me to see the need for light in the lower section in order to clearly identify those darker filament types in the lower AMS. I used a strip light I already had and ran a USB cord I got from Amazon that had a built in on/off switch. The only problem was the weight of the cord would slowly pull the light strip off its surface. Hence the design. I designed this switch harness and attached it to my AMS shelf that kept the weight off the cable.