They need to happen to be really tricky dogs as I have not seen a dog demolish just one of these. But to anyone who has defied the impossible, I recommend the aptly named Kong Excessive. You could regulate the dimensions of the openings to range the degree of difficulty. https://petshopdubai07417.kylieblog.com/36966466/the-smart-trick-of-dog-toys-with-squeakers-that-nobody-is-discussing