Build a real-working wrecking ball—then smash away! Our kit comes with everything kids need to build a medieval-style wrecking ball—including a step-by-step guide, wood, glue, a kid-sized hammer and more. And when children are done building, they can put their machine to the test—with exciting activities that introduce them to concepts like cause and effect. Kit includes everything needed to build the wrecking ball—plus eight super-safe foam blocks for demolishing. Largest building piece measures 10" in length.