It's a little piece of plastic, about the size of a tic/tac with metal inside that will allow you to connect 2 pins on an electrical board together which is necessary to get the Walmart version to fire full auto. Radio Shack will have them on the cheap but if there are any computer stores nearby you could probably get a couple for free. They are usually used in computers to set the drive and motherboard configuration. There are other ways to short the pins together (solder or wire) but neither are as safe or reliable as the jumper. If you have any more Qs feel free to PM me so we don't clutter this thread up.
