ZipLit LED Zipper Pull Light A simple, yet indispensable little illumination device, threaded with durable cord that's easy to loop, cinch and attach to the end of almost any jacket, coat, backpack, tent door or purse zipper. Just as easy to remove. Encased in durable, water-resistant, plastic housing. The bright L.E.D. provides instant visibility whenever you need it, so you can see your surroundings better and others can see you. The perfect way to increase the personal safety of kids walking to school, dog walkers, runners and campers. Includes extra set of batteries. Measures 3/4"Dia. x 2 1/2" overall.