Redefine gravity and challenge your friends with the Aerobie Sonic Bounce balls for kids! Engineered with the intention to be the highest bounce ever, the Sonic Bounce is built with high density foam material, using geodesic geometry and scientific construction to provide super high bounces! The spikes on the ball act as conduits for kinetic energy, providing more rebound and resulting in a higher bounce as compared to traditional sphere-shaped outdoor play balls.