2 years & up. Kids will be jumping to new heights with the Bouncing River Stone! Inspired by stepping stones in a river, this Bouncing River Stone features a soft base and a hard-top platform supported by three strong steel springs to enable bouncing. This River Stone physically challenges kids as the bouncing motion requires adjustment through the ankles and legs, which strengthens the proprioceptive sense. Use the Bouncing River Stone on its own for special motor training activities or use other River Stones together for more play possibilities.