Three modes: fast flashing LED, flashing, and constant on. Plus, it's USB rechargeable. Perfect for commuting to school or work!!! For jogging, walking, running, and walking your pet... To prevent nighttime accidents, please have your children wear them. Great for nighttime safety on the way home from cram school or club activities. These are essential for those who are weeding along the road. You can't be seen by drivers when you're crouching in the dark. You can also feel safe having your children wear them when you go camping. Sometimes it's pitch black in certain places, and even adults can feel scared of the dark! Being able to visually confirm "I'm here!" "I'm here!" "I'm here!" leads to accident prevention. Available in five sizes: approximately 80cm (160cm circumference), 67cm (134cm circumference), 57cm (114cm circumference), 47cm (94cm circumference). Please note that there may be slight variations in size depending on the measuring method.