I cannot stress enough how this is the best $4 I have ever spent. I have a pitbull who lives to play fetch and I've never been able to tire her out. she gets ten times the exercise me using this thrower than she would if I were throwing the ball myself. I did buy some of the small sized Kong balls as she's a little rough on balls and it works great with those however the ball that it came with is still intact after two weeks of every day play.