This is for USB current measuring, snooping, and troubleshooting of USB devices and USB connections. Case holds two LEDs one for input (power light) and one for output (power light). I can post a wiring diagram if asked for, but pretty strait forward idea.Parts: LED bezels http://www.taydaelectronics.com/leds/led-holders-bezels/5mm-bezel-led-panel-mounting-clip.html USB A female: http://www.taydaelectronics.com/usb-type-a-female-connector.html USB B female: http://www.taydaelectronics.com/usb-type-b-female-connector.html Use any color LEDs (5mm) for power check lights on the input and output. I planned to use some screws I had lying around for posts to connect end to end with alligator clip leads.