I'm using this with the Kong squeaky tennis balls, although it seems to work with just about any of the balls my dog brings me at the park.  I have a bad shoulder, so I was hoping this would allow me to throw the ball without pain.  No luck there, but what it DOES allow me to do is to throw the ball a lot farther, and to pick it up off the ground more easily.  I've gone from being only barely able to play with my dog to being the 'fun mommy' at the dog park.  It's really improved my relationship with my dog, and I'm very grateful for that.  It's also pretty durable: I've dropped it several times and even dropped things onto it, and it still works perfectly.  Definitely worth the price.