5 years & up. Explore the secrets of staying balanced! Discover how acrobats manage to not fall off while walking on a tightrope or doing handstands with the Koontz™ Walking the Tightrope kit! Did you know that the center of mass is an imaginary point on a body where all of its mass is considered to be concentrated? To stay balanced, an acrobat needs to position his center of mass over the base of his body. Made from durable, lightweight, recyclable cardboard. Includes simple step-by-step instructions and a fun activity booklet. 17 pieces.