If I could I'd give this system another star I would. An active border collie and a 50 year old shoulder do not make for hours of fun. With a flick of her wrist our 10 year old daughter can launch a ball far enough to make it a lot of fun.  And because it also accepts a regular tennis ball we're never out of play time. (Personal note: I appreciate the fact that the manufacturer did not make a proprietary ball size. I would probably NOT buy it if they did.  Because we can use any ball I will recommend it to so many more people they'll receive a hundredfold more sales)