This is a replica of a hinged counterweight trebuchet that was used during the middle ages. The details have been pared down to make this as simple as possible. Everything you need to assemble and launch is included with the kit: wood glue, bouncy ball, pre-cut and pre-drilled wood, vinyl pouch, trigger and fully illustrated instructions. With a full counterweight box of rocks, batteries, coins, or anything else you can launch the bouncy ball 30ft! Have fun launching dog treats, parachute army men, blueberries or anything else. It's a great learning experience with its hands on building and simple but in-depth physics. This kit has won science fairs, been used for summer camps and after school programs, featured in "Best of" shopping magazines, in-class demonstrations and more. It's fully adjustable release pin makes it the most customizable mini trebuchet for sale. Use it to learn about medieval siege weapons, physics or to destroy your building block castle.