Object Permanence Box w/ Tray This material develops hand-eye coordination and indirectly allows the child to experience object permanence. 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. The set consists of a box with two holes, a tray, and a white plastic ball.