http://www.ApogeeRockets.com - This is a short introduction to the Estes Viking model rocket kit. It is a bulk-pack of 12 rockets, which makes it great for schools and for birthday parties. What makes it unique is that the fins can be glued to the tube in any one of the four sides. This allows each rocket to look different, even though they start out the same. You can compare which of the designs your students build performs the best - with just changing one variable.