Great irregular bounce Helps clean teeth and condition gums Made from irrestistible natural rubber A new addition to the Kong range is the ultra-bouncy Kong Jump'n Jack, which has a completely unpredictable bounce and is great for sharpening a dog's reflexes! It also has specially designed grooves which close over teeth and gums, even those at the back of the mouth. Ideal for use with Kong Stuff'n paste or other flavoured toothpastes.