Each 11 1/2? x 1 3/8? bracelet is made of PVC and reflective material. It comes with one replaceable 3V-CR2032 battery installed. Three flash modes – fast flashing, blinking and steady, it will keep you visible to drivers and other pedestrians when you’re running, riding, walking, jogging, camping, etc outdoor sports, or even add one to your dog’s collar for safety!