SureFire's Fury Dual Fuel IntelliBeam can be powered by either a USB charged SF18650B battery or two 123A lithium batteries. When using the SF18650B battery, the Fury can produce an extremely powerful beam of 1500 lumens to turn night into day with an illumination distance of up to 315 meters. If the two 123A lithium batteries are installed the Fury provides a 1100 lumen beam at a distance of 255 meters. The unique IntelliBeam technology automatically adjusts the power output to the most optimal setting between 15 and 1500 lumens depending on the environment. Alternatively, double clicking the tail-cap overrides the auto-adjustment function. The Fury DTF is more than just a pocket sized flashlight, it's a pocket sized spotlight and built to stand up to the worst of conditions. Features of the Fury DTF: Auto adjusting IntelliBeam technology Powered by either a single SF18650B or two 123A batteries 1500 lumen output (SF18650B) 1100 lumen output (dual 123A) 315 meter illumination distance (SF18650B) 255 meter illumination distance (dual 123A) SureFire Fury Dual-Fuel Intellibeam Auto-Adjusting 15-1500 LU LED Black Flashlight FURY-IB-DF