Police Security Twin Power 2000 Lumens Flashlight. It is a groundbreaking, patent-pending technology ultra-bright flashlight that redefines traditional Dual Power flashlights. Unlike Dual Power, which requires two separate battery cartridges, the Twin Power flashlight operates seamlessly with a SINGLE cartridge. The cartridge holds a built-in 21700 rechargeable battery for primary power, and 3AA alkaline batteries for backup. With this innovative design, you'll never face the dilemma of drained power. Simply toggle between alkaline and rechargeable battery sources with the touch of a button, ensuring uninterrupted illumination whenever you need it. Equipped with battery level indicators, this flashlight guarantees you'll never be left in the dark.