Made from a unique, easy-to-clean mesh material. BEST FIT Muzzles are lightweight, breathable and adjustable, providing total comfort for dogs. This is a TEMPORARY muzzle to inhibit biting, control while grooming, chewing and barking, while still allowing dogs to pant . Size #8 11.5 Inch Nose for Rottweiler, Mastiff and St. Bernard size dogs. Note: Due to verying sizes of dogs within breeds it is recommended that you actually measure your dog for proper sizing. Here is a quick guide. Start at the eye of the dog and measure down to the tip of the nose to get an accurate muzzle length. To measure for the proper circumference, start one inch below the eye and measure all the way around the nose of the dog. For proper muzzle fit, you should add length to each circumference measurement. An addition of one-fourth of an inch to half of an inch is required for a small dog. Large dogs require an additional half inch to one full inch.