The Beacon clips to pet collars or human clothing giving you peace of mind anytime you and your companion are out and about. Add a measure of safety by allowing you and your pet to be seen up to 1/2 mile away. In today's fast paced, heavy weight SUV world it is better to be seen than the alternative. Keep track of dogs in low light situations. Clips to dog collars and to human clothing. 130 hour battery life Compact size. Light weight Waterproof--submersible to 300 feet. Lifetime bulb never needs replacing Length: 1.75" Diameter: 0.875"