Probably the best dog light in the world. Waterproof, resistant and easy to see up to 5 km away. Battery life is up to 250 hours for flashing and 100 hours for steady light. And if you run out of battery, it's easy to change it yourself. The Orbiloc light is safe for your dog and good for the environment as it is a quality product you can use for many years - and of course it comes with a 3-year warranty. Quick Mount and the adjustable strap are included so you can attach the light to a collar or leash.
If your dog is long-haired, it may be a good idea to hang the light from a carabiner. You can find all the accessories here