The ball tracker comes with balls in Red, Yellow, Blue, Green .It practises precise hand movements while sending information to the brain as well as develops hand, wrist and finger control - also known as "refined hand movements". Sensory aids for 0 to 3 years old can exercise children's hand-eye coordination through simple movements. It is made of high-quality wood, good workmanship, moisture and abrasion resistance, smooth and burr-free.