KONG Extreme represents the most durable version of the original KONG toy. The ultra-strong black rubber compound is recommended for power chewers. Satisfaction guaranteed. Extreme is the hardest, most durable KONG available on the market today! KONG toys are enthusiastically used and recommended by veterinarians, trainers, dog professionals and satisfied customers world wide. Why KONG Toys Rule So, how do KONG toys benefit dogs? First and foremost, they help keep dogs occupied and mentally stimulated while their Pet Parents are away. KONG toys have an unpredictable bounce that has been known to cause spontaneous eruptions in playtime fun. Regular use of KONG toys can also improve oral health. Supervise your dog's use of KONG Toys until you are confident they can be used safely without supervision. This is especially important with tenacious chewers! Recommended for 60-90lb dogs.