The CombatLight that automatically adjusts to your lighting requirements Seamlessly shifts from 15 to 1,500 lumens, and everywhere in-between Flexible Dual Fuel feature allows use of 18650 rechargeable or 123A primary battery power The P1RZ-IB-DF is a combat flashlight with a brain. The CombatGrip is designed and built specifically for tactical use in conjunction with a pistol, while the 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. Its precision microtextured reflector creates a smooth, far-reaching, hybrid beam with a bright central area and enough spill light to help you maintain awareness of your surroundings. Two simple clicks of the tailcap will override the auto-adjustment function for maximum output on demand. The P1RZ-IB-DF's click-on/off tailcap switch provides ergonomic, foolproof activation even under the most stressful conditions. With a high-strength aerospace aluminum body that is Mil-Spec hard anodized for extreme resistance to abrasion and corrosion, the P1RZ-IB-DF thrives in the harshest environments imaginable.