A Thestral is a breed of winged horses with a skeletal body, face with reptilian features, and wide, leathery wings that resemble a bat's. They are very rare, and are considered dangerous by the Ministry of Magic.
A dog collar is a piece of material put around the neck of a dog. A collar may be used for control, identification, fashion, or other purposes. Identification tags and medical information are often placed on dog collars. Collars are also useful for controlling a dog manually, as they provide a handle for grabbing.
You can use a martingale collar on any breed of dog, and they can be custom made to suit your pet. They can be plain or fancy, for everyday use or for outings. They can also come with a lining so that the collar doesn't rub your dog's neck. The most important part of buying a martingale collar is to measure your dog's neck so that it will fit properly. You can buy adjustable or made to fit martingale collars, whichever you prefer.