goDog Retrieval screwBallz add a twist to traditional fetch with bumps that create fun and wacky bounces with every throw. Easily destroyed traditional tennis balls are a known hazard for dogs because once they’re broken they can present a serious choking hazard. screwBallz feature patent pending Tough Core Technology that adds a durable foam insert and bonded seams to create a more durable, safer tennis ball for longer lasting fun. Sized for larger pets, the large screwBallz are brightly colored and easy for pets and their humans to find. This toy is intended for interactive play and is not meant for use as a chew toy.