Blinking Light Marker with Mini-Clip. High-Visibility Blinking Light Marker is watertight and flashing with a quick twist of the cap. Easily attaches to collar or leash with metal snap. Great for late afternoon walks in the fall and winter months. A must for keeping track of dogs at night. Easily replaceable CR2032 battery is widely available where batteries are sold. Will blink continuously for up to 2 weeks.