The FURY-IB-DF takes the automatic adjusting output of our Fury with IntelliBeam technology and increases the maximum output to an astounding 1, 500 lumens. "Df" stands for dual fuel, which means this versatile pocket-sized searchlight can be powered by either two 123A lithium batteries or a single economical 18650 Lithium-Ion rechargeable battery. Our proprietary IntelliBeam technology automatically and seamlessly adjusts the virtually indestructible LED's output to the optimal setting anywhere from 15 to 1, 500 lumens - based on your environment, so there's never any hesitation or fumbling to manually set the output. Should you desire maximum output on demand, two simple clicks of the tailcap override the auto-adjustment function. Everything else is pure Fury, with a precision micro-textured reflector that creates a smooth, far-reaching beam with a bright central area and enough surround light for situational awareness. A High-strength, lightweight aerospace-aluminum body is knurled for a secure grip and mil-spec hard anodized for extreme resistance to abrasion, corrosion, or just about anything else you can throw at it..