Bought for my almost completely blind and deaf dog. He can see a flashing amber light in the dark when he is less than 6 feet away and looking his way. I can't hear him bouncing, but he can hear a squeak when it's in his mouth. He loves chasing the ball. This is his only joy! Otherwise it will always be a silent black hole. These balls are enough for about 10 rebounds! so sad! They are also very thin. It would be better if they were made! Buy them because there are no others that are better. need yellow. I can't find anything permanent anymore!