Howdy, After seeing Redline's electronics handiwork on Alt. Shockwave a good while back, I was inspired to do one myself. However, I was convinced that I could build everything into his forearm, precluding the need to mount circuit boards or route wires elsewhere in and around his body. Due to the obvious space restrictions, I knew that I would have to keep it simple. The setup I imagined would really only consist of a power source, an LED, some type of switch and a few bits of metal, wire and plastic to keep all the stuff in place and complete the electrical connections. My first task was to find a small LED, which I got from Radio Shack. Unfortunately, the only LEDs they had in the size I wanted were red...oh well. Task 2 was to find a power source that could light the LED and still fit inside of the forearm with the rest of the junk. The LED is a 3V unit, so I picked up a pack of tiny hearing aid batteries, which were 1.5V each (I would need to use two in series to make the LED work). I quickly discovered that the batteries I got were still much too large to fit, so I went to a battery store (that's right, a store that sells nothing but batteries and battery accessories) and found a couple that would HAVE to work...as they were the smallest batteries they had! Task 3 was to figure out how the hell to put it all together and turn it on and off. After looking at the size of the batteries alone, plus the small space I had to work in, I decided against trying to use any kind of normal switch...so I got the bright (no pun intended) idea to use the cannon itself as the switch. As you can see in the first pic, the LED is located inside of the cannon. I simply drilled out the first half inch, or so, of the cannon and epoxied the LED inside of it. I then ran the leads through the black plastic holder at the base of the cannon and into the forearm where I bent the leads back around the base of the holder, as shown. Next, I made a battery holder out of a short length of white styrene tubing which is glued to a small piece of flat styrene sheet (which is beneath the tubing in the pic). I then inserted a small spring through the tubing to act as the electrical connector between the two batteries. The final step was to install a small metal contact at each end of the battery holder. The contacts were cut from a super thin sheet of stainless steel and they are there to complete the connection between the batteries and the LED leads. Operation of the LED is simple...just twist the cannon so that the LED leads rotate and make contact with the battery contacts. The red LED isn't as bright as I would like it to be, but I'll be damned if it doesn't work. Here are the guts: Here he is in action: Not sure what size class the batteries are, but they are Energizer 377/376 1.55V silver oxide units. The package also says that they are direct replacements for SR626W and SR626SW batteries. Hope that helps! Show some pics of what you come up with! Here's another pic...taken in lower light: Oh yeah. When the forearm is assembled, you just rotate the cannon clockwise to turn the light on and counterclockwise to turn it off (while looking down the barrel).