Goughnuts Heavy Duty Black RingCarbon reinforced rubber Solid rubber No indicator core Made for power chewers Guaranteed for life Toughest Goughnut ring yet Always supervise your dog chewing [split] The Goughnuts Heavy Duty Black Ring was engineered to give dogs a safer, tough toy. This ring is made from a natural rubber in the USA employing revolutionary carbon reinforcement technology. The new Heavy Duty Ring is the most durable Goughnut yet made for true power chewers under