Worn around the upper arm, our Nite Ize LED Marker Band is the perfect way for early morning/nighttime runners to stay safe and seen in the dark. Made of reflective, durable material, it holds an efficient (100,000 hour) LED bulb and flexible polymer strip that can be seen up to a mile away. The elastic band and quick release buckle closure make it simple to adjust a comfortable fit. Chose from three modes—steady glow, continuous flash, and off. Powered by two easily replaceable batteries