This is one of Petzl's most powerful compact headlamps. With Reactive Lighting technology it will analyses the ambient light and automatically adjusts the brightness. This Head Torch is intuitive, with a single button for easy control over all torch functions.REACTIVE LIGHTING sensor analyses ambient light and automatically adjusts brightnessUltra-bright and lightweight: 900 lumens at only 100gReflective 2-part detachable, washable headband for night visibilityErgonomic adjustable headband adds stability in dynamic activities eg. mountaineering, trail running, skiingSingle button controls all lamp functions (ON/OFF, lighting modes REACTIVE/STANDARD, brightness and lock)Five-level gauge precisely monitors battery charge levelTwo beam patterns (flood or mixed) give lighting for proximity vision, movement and distance visionLithium-Ion 2350 mAh battery, rechargeable via type B micro USB portLOCK function avoids accidental turning on during transit or storage, or locks lighting settings during activityHeadlamp can be tilted upward for seeing ahead when worn around the neckLight output: 900 lumens (ANSI-FL1 STANDARD)Weight: 100gBeam pattern: flood or mixedEnergy: 2350 mAh Lithium-Ion rechargeable battery (included)Charging time: 6 hrsWatertightness: IPX4 (weather-resistant)Certification(s): CE_