My dog loves squeaking tennis balls above all other toys. So when I got these ones for him, he was delighted. They do not squeak very easily, he has to put in some effort to make them squeak but they do. These tennis balls are neatly made, they look good and are a little smaller then the size of a regular tennis ball, which fits in my dogs mouth more comfortably.My dog is able to squeeze down on the tennis ball without straining his jaw, which I am pleased by. I have had these kinds of tennis balls for him before, but those were much more difficult for him to bite down on, they would sometimes make his jaw very sore afterwards.Not the case here, these squeaking tennis balls are great, they are a better size for a medium sized dog and work very well with training and or exercise for your dog. If your dog/s love squeaking tennis balls then you will be happy with these.