I actually got the LEDs from Radio Shack, they were the square type, the round ones won't fit, they're too deep. Then I found some small 1.5 volt watch batteries, and staggered three in each arm so they didnt interfere with the original screw posts, and installed a small switch in each elbow. I used styrene as battery holders/insulators, and found a piece of thin stainless steel that I cut into strips, to connect the batteries in series, totaling 4.5v. I would unscrew the arms to take a pic, but it would screw up the forarm stickers , so ill have wait until the batteries are dead. But if you look in a couple of the pics, you can see the switches at the elbows.