This dog muzzles has 7 different sizes, which means that it can be suited for most dog sizes and dog ages. They are very easy to fit and use with a fully adjustable strap and buckle as well. It's great to meet your different needs with the multiple choices and solving your problem easily. Anyway, if you have no idea about your dog's mouth size, this product will help you. Multi-Function Dog Muzzle: This dog muzzle is a prefect solution for a lot of problems. For example: Prevent the dog bitting, prevent the dog eatting around, prevent the dog licking wounds and the dog barking. Suitable for most dogs: Teddy, Chihuahua, Miniature pinscher, Schnauzer, Samo or other pets. It is a really nice helper for home, travel, pet training, pet store, pet hospital and vet. Easy to Wear and Clean: The combination of double Velcro and buckle makes it easy to put a dog shield on your dog. Any excess strap length can easily be secured with a hook and loop fastener to prevent loose ends as well. It is easy to clean and also can be washed by the washing machine. Adjustable Design & Reusable: These anti bite muzzles are designed with a fully adjustable strap and buckle. This design will help you easy to put on or quick release buckle, it's very convenient and simple to adjust the right size for your dog. Besides, the material is wear-resistant, dirt-proof and easy to be cleaned, so that it can be used again and again. It's surely the reusable product and good companion for your needs. Please Note: Choosing the right size online can be difficult, so charts and measurement instructions are provided for convenience, and if you have any difficulty in finding the right size, we will provide strong customer support and will work hard to resolve your problem