Responsive OutputThe Nitecore SENS Series of LED flashlights features advanced technology that responds to your needs instantly. Each model is fitted with remarkable circuitry that dims and brightens automatically as you point the light from the floor, to the ground ahead, to the horizon. Known as Advanced Dimming Technology (ADT), Nitecore's patented system offers the LED's brightest outputs when the light is oriented ahead, towards the horizon, giving you the farthest throw. As the light is pointed downwards, the output will dim twice. Once at 45 degrees and again when pointed directly at the floor. This responsive feature saves your battery life and reduces eye fatigue caused by high outputs reflecting off of close surfaces. Ultra-Small DesignThe ultra-compact SENS Mini is powered by a unique and powerful CR2 lithium battery. At just under 2.25 inches, this light fits neatly in any pocket, purse, or hand bag, making it easier than ever to keep an efficient and brilliant light on you at all times. The simple and intuitive twist-bezel interface makes operating this light a breeze. Simply rotate the head of the light to turn on the light. ADT will automatically be activated. The SENS's auto-dimming feature can also be turned off using the twist bezel, allowing you to keep the SENS Mini in its 170 lumen high mode regardless of where it is pointed. Nitecore constructed this light out of military grade hard anodized aluminum that is scratch resistant, impact resistant, and water proof up to IPX-8 water resistance standards. Features and Specifications: Dimensions (L x Head Diameter x Tail Diameter): 2.24" (57 mm) x 0.77" (19.8 mm) x 0.72" (18.5 mm) Weight: 0.68 oz. (19.4 g) without battery Uses 1 x CR2 battery (Batteries not included) Uses 1 x CREE XP-G (R5) LED with 50,000 hour lifetime Output: 170 lumens (high), 50 lumens (mid), 20 lumens (low) Runtime: 1 hour (high), 4 hours (mid), 14 hours (low) Maximum throw of 226 ft. (69 m) Acceleration sensor and micro-computer sense position of the flashlight and adjust output accordingly Reverse polarity protected board voltage circuit is compatible with primary or rechargeable Li-Ion batteries Convenient one-handed operation Body material: Type III Military Grade Hard Anodized Aluminum Water resistant to IPX-8 standards Impact resistant to 4.92 ft. (1.5 m) Tail stand capable Comes with: keychain, spare O-ring