Wow. This was a major pain in the ass. I put an LED inside WFC Megatron's cannon. I used one of the finger lights that someone (I don't remember who) posted a while back. I had to heavily modify the inside of the cannon so the light and batteries would fit. Then I had to rig a switch so I can turn it on and off. The switch is on a little bit of an angle but that couldn't be helped. I am very pleased with how it turned out. My only problem with it is that the light seems to dim after it's been on for a few seconds. I painted it in flat black and then dry brushed it. I am going to paint in details and also paint the entire figure. This was my very first attempt at putting an LED in anything.