The pet blinker reviewed on Cool Tools is nice, but I’ve used a larger one which I’ve found works much better. They give a full 280 degrees of light, and being a much larger surface area of illumination is a real advantage. I can see my dog in the deep underbrush, even if he’s laying down (where the “dangling” type lights get blocked by leaves and front paws.) We get about 5 months of use out of a single battery in flash mode, which we run for about 1.5 hours a day. We could get longer, but the light starts to dim a bit after that time period.