This is the world's most versatile flashlight, designed for the U.S. military to provide 20 tactical light functions in one lightweight unit. Slightly longer than a cell phone, the flashlight has a 185° articulating head that houses four different LEDs. It has a bright 1/2-watt bright white LED housed inside a waterproof, gasket-sealed polycarbonate lens used for general lighting purposes. Its red LED is used for ambient illumination by military aviators at night, and can be used at night for reading maps or observing insects. The green LED is used to preserve a soldier's night vision; can be used with night vision goggles during wildlife observation. The blue LED allows medics to easily identify injuries at night. The lights are controlled by rotating the on/off switch's rotary collar. All lights can be set to one of four intensity levels by pressing and holding the switch--5%, 20%, 50%, 100%; each can be set to strobe by double-clicking the switch, resulting in five possible settings for each LED. Its impact-resistant nylon case mounts to the U.S. military's MOLLE system, and easily fits onto a belt or backpack strap for hands-free use. Two AA batteries (included; also accepts lithium batteries) provide up to seven hours at 100% intensity or up to 100 hours at 5% intensity for the white LED. The battery cap screws into place and is attached to the case with a tether, eliminating the chance of dropping and losing the cap in the dark. A built-in cord attachment hole allows you to attach a lanyard. 4 1/2" H x 2 1/4" W x 1" D. (5 oz.)