The XT DF has a maximum brightness (primary setting) of 600 lumens, with a secondary light level that's user-programmable at 15 or 150 lumens, or strobe. In keeping with our emphasis on intuitive design and simplicity in our law enforcement tools and training, activation is via a single pressure switch on the tail cap-press once to activate the primary/high setting, twice ("Double Tap") to activate the user-programmed secondary mode. Setting the secondary light level takes just seconds?simply twist the bezel open to activate programming mode, tap the gray selector button to cycle through the levels until you reach your chosen setting, and twist the bezel closed to lock it in. A 3-position twist selector on the tail cap allows choice of intermittent, constant-on or locked. Dual Fuel technology means you'll never be without a power source?it runs with either a rechargeable 18650 battery (included) or 2 CR123A primary (single use) cells, sold separately. The 18650 battery charges inside the flashlight, using the supplied cord and adapters, or any micro USB phone/electronics charging cord?no separate battery charger needed. The XT DF is machined from 6061 T6 aerospace aluminum, type III hardcoat anodized in a proprietary matte black finish. The barrel is wrapped in our exclusive, all-weather foamed vinyl grip. Premium components include Cree XPG LED, gold-plated connectors, polished aluminum reflector and optical glass lens. Includes high-performance ASP 18650 rechargeable battery, battery storage case, retractable charging cord, wall adaptor, car adaptor, adjustable/removable pocket clip, and zippered ballistic travel case.