Never worry about turning your tail light on (or off) again. Cateye's Reflex Auto Taillight has optic and motion sensors, so when darkness and motion are detected your light turns on instantly. One super-bright LED and 4 small LEDs give you more than 180 degrees of visibility. It has 5 different modes so you can customize the pattern and run time. And even when it's not on, it provides bright reflectivity that helps you stay seen as well.