This incredible building set lets kids put together their own spectacular, spinning show! The interchangeable pieces slide together easily for no-fail designing. Children simply stick the gears onto a magnetic surface...fit them together any way they like...then turn one of the built-in handles to set the whole colorful creation in motion! Sturdy plastic set consists of 22 magnetic gears in 2 sizes. Large gears measure 3 3/4". Magnetic board sold separately.