Muzzle for dogs should be selected very carefully. Proper size is not only important for the dog to be not able to take it off but also due to a way the dog regulates the body temperature which is done by the mucous membranes in the dog mouth. Our shop offer muzzles in various sizes and prices. We recommend you measure the dogs mouth to know what size to purchase. Veterinarian opinions show that dog should be able to open the mouth freely because he regulates the temperature by panting. Second thin is the length. We measure it from the top of the nose to eyes. The size of the muzzle should be slightly larger than measured section to avoid hurting the dog.