with a leash. Special-purpose collars and attachments Stud collars, also called wolf collars, protection collars, or spiked collars depending on the attachments, are collars fitted with metal studs, dulled points, or sharp points that traditionally prevented another animal from biting the dog's neck. Commonly, spikes are hand-set and tightly riveted for extra security. This type of collar dates back to ancient Greece, when dogs protecting livestock were given nail-studded collars to protect them from wolves or other predators. In modern societies, stud collars are more commonly considered a fashion accessory. Reflective collars, usually made with nylon webbing, incorporate reflective tape that ensures that the dog will be seen at night by approaching vehicles. A lighted collar (or collar light, dog light) is a collar that emits light in order to make a dog more visible in the dark to their owners and more importantly, nearby motorists. It is not designed to help a dog see at night, as it is well documented that dogs have very good vision in low light conditions. Most lighted collars utilize one or more light emitting diodes for the light source and can be of virtually any color, although red and blue are most common. Power is provided by one or more batteries, most common types being AAA and lithium coin cells to minimize the added weight to the collar. A flotation collar (or buoyant collar) is a buoyancy aid designed for dogs. Although it is not designed to be used as a life preserver or life jacket, it can provide additional buoyant support for the head of a dog when in the water. It is often used in canine hydrotherapy services to assist in the rehabilitation of injured dogs. The collar may be constructed of closed cell foam material that is inherently buoyant or be of a type that is inflated with air. Medical collars Flea collars are impregnated with chemicals that repel fleas. They are usually a supplementary collar, worn in addition to the conventional buckle collar. Elizabethan collars, shaped like a truncated cone, can be fitted on a dog to prevent it from scratching a wound on its head or neck or licking a wound or infection on its body. Fashion collars Dog collars are also used to convey the owner's style and have been used as a status symbol. The oldest known fashionable dog collars come from ancient Egypt, dating back