Kong toys are an extremely tough, hard rubber puncture resistant toy. This is one of the toughest toys on the market! The opening in the center of the toy is ideal for stuffing treats, dog food, peanut butter, or your dog's favorite treat to keep your dog busy and out of trouble. We recommend choosing the correct size Kong toy for your dog. The small is great for dogs up to about 20 lbs, the medium for dogs up to about 50 lbs, the large for dogs up to about 100 lbs, and the extra large for dogs bigger than that.