I purchased the 6" red ball for my power chewer. He cannot get it in his mouth which is a good thing. It doesn't go under the couch, has a bit of a bounce on the tile floor and provides lots of exercise for my pound puppy who is 6yo and full of play. He uses his nose for everything so this ball was perfect because he can flip it to bounce it and then batt at it with his paws to chase it. He has even bounced it into a crate. It is a little noisy on the tile floor because it is made of hard plastic, but I just put it up after a supervised playtime.