The PowerTac E3 is the ultimate everyday carrying key chain light. It combines a compact size and amazing 168 lumen maximum light output with only one AAA battery (not included). The E3 also comes with an easy to use interface and three different brightness levels plus strobe. The E3 outputs an amazing 168 lumens on high and 50 lumens on low, which is good for low light situations with super long run time. It's durability, shock resistance and rugged build quality make it the key chain light to go everywhere your adventures take you.