These guys have been on my Dad's bookshelf for as long as I can remember. Super fun to wind them up and watch them vibrate across the shelf until one crashes into another and sends it plummeting to the ground (very durable don't worry). There are six of them and just one of these jittery creations is going for $15 on most sites--just to explain what might seem like a rather high price. Each one will be individually wrapped in paper and sent in a box with the others.