Waterproof, impact resistant, and visible up to 3 miles away, this is the light that Danish search-and-rescue teams rely on to keep their dogs visible in dark and dangerous conditions. The low-profile LED safety light fastens anywhere on your dog's collar via a clip or hook-and-loop strap (both included). Switch on by simply rotating the lens. 100,000-hour bulb, 250-hour battery life. Weighs less than 1 oz.