KONG Extreme Dog Toy for Aggressive Chewers – Ultra Durable Natural Rubber & Treat DispensingExtra tough rubber and an innovative design that challenges pets for hours of fun. These Kong Extreme Dog Toys are great for pets that are aggressive chewers. The Extreme (Black) Series of Kong Dental Toys give dogs a real chewing workout that helps clean teeth and gums. The Kong Extreme Dog Toys are made of puncture resistant rubber for unmatched strength, durability, and bounce. Non splintering, non abrasive, and do not get sharp when chewed