The Pro DF (Dual Fuel) flashlight boasts a primary setting brightness of 500 lumens when used with the included 18650 rechargeable battery, or 610 lumens with optional CR123A primary cells. The secondary light level is user-programmable at 15, 60, or 150 lumens, or strobe. In keeping with ASPs emphasis on intuitive design and simplicity in their law enforcement tools and training, activation of the Pro light is via a single pressure switch on the tail cap press once to activate the primary/max setting, twice to activate the user-programmed secondary mode. A 3-position twist selector on the tail cap allows choice of intermittent, constant-on, or locked. Setting the secondary mode takes just seconds?simply twist the bezel open to activate programming mode, tap through the levels until you reach your chosen setting, and twist the bezel closed to lock it in. A blazingly-bright primary setting, and programmable secondary setting (low, medium, high and strobe)?it s like having five lights in one. Includes high-performance ASP 18650 rechargeable battery, battery storage case, retractable charging cord, wall adaptor, car adaptor, removable pocket clip, and zippered ballistic travel case. Product Specifications Length: 6.25" Diameter: 1.25" Cell: One Rechargeable 18650 Battery (Included) or Two CR123A Batteries Max Output: 500-610 lumens (610 using CR123As) Run Time: 1.75-4.5 hours Max Beam Distance: 174-188 meters Weight: 5.12 oz. (with batteries)