My sister got this Turbospoke "exhaust system" for Noah this Christmas. It's distributed out of Ireland and she had found out about it on the interweb. Today we attached it to Noah's bicycle so we could try it out. It's 18 degrees outside, so we decided to work on it in the basement. The system is like the old baseball card trick but on steroids. It comes with different cards that each have a different sound. There is a small plastic chamber that the card slides into and the chamber leads to a small plastic canister that helps to amplify the sound. It's pretty ingenious actually. He's dying to try it outside; we may have to suit up and brave the cold.