Did you know that most Veterinarians recommend using rubber balls instead of tennis balls?
Tennis balls are designed for an asphalt court and have strong fibers that protect the ball as it is sent hundreds of miles an hour from a tennis racquet. These fibers act as a scouring pad on a dogs teeth damaging the protective enamel on their teeth which contributes to dental disorders including bad breath.
A tennis ball also absorbs odors, and bacteria when rolled around in the dirt or grass and mixed with dog saliva. Then you have to pick up the dirty, smelly, dog drool filled ball and throw it! Nobody wants to do that!
This is why a Nero Ball is safer, cleaner and better at keeping teeth healthy than tennis balls.