Kong Blue’s are 25% stronger than regular Kong toys (in excess of 3800 psi). They can also be stretched up to 9 times their original length and they’re highly puncture resistant. It’s now being used by powerful chewers around the world like police K-9 teams, drug enforcement and military K-9 teams, AKC competition trainers, Shutzhund Clubs and more. Puncture resistant, bouncy, and chewer friendly. Satisfies a dog’s natural need to chew cleans teeth and conditions gums. Thick, flexible walls that keep springing back for more! Non-toxic, nonabrasive, non-splintering, and does not get sharp when chewed. Recommended by veterinarians, trainers, dog professionals and satisfied customers world wide. Stuff it with your favorite pet treat and watch your dog have loads of fun. I stuff mine with carrots.