Montessori Object Permanence Box with Tray and Ball A child has to drop the little ball into the hole in the box. The ball will roll out of the box and into the attached tray thus allowing the child to experience object permanence by seeing that the ball did not just disappear. It practices precise hand movements while sending information to the brain as well as develops hand, wrist and finger control - also known as "refined hand movements". With repeated use of this material, the child learns how it feels to succeed when he has achieved a goal on his own. We provide 30 Day money return guarantee, as long as you find the purchased item is different from our listed description and condition.