I bought this for a small dog and described for small dog balls but it came without balls except for one and it was the large tennis ball for a large dog. The gun only holds the large ball for big dogs and not the small and medium size balls for smaller dogs. Amazon has a much better deal where you can choose size of gun and comes with 5 balls vs. just one here and you can select size of balls and gun and they all shoot same distance.
All my dogs love this especially my husky puppy...when I take them out to the park they can't wait for me to pull this thing out. It's also great too because hubby has a pre existing shoulder injury, with this ball launcher he can still interact with our fur babies without hurting himself.