This Headlamp is made to be technical yet compact, with a comfortable fit! It has a large max lumen output of 400. Its battery is rechargeable via micro USB, meaning no more need for carrying the weight of extra batteries. It can withstand harsh, wet conditions and can even operate a meter underwater for half an hour. A great bit of kit for taking up any mountain!Rechargeable: Powered with integrated 1500 mAh Li-ion battery with micro-USB charge port400 Lumen max outputRecycled elastic headband featuring comfortable next to skin Repreve fibre constructionIP67: Waterproof-Tested to operate at least 1.0 meters underwater for 30 minutesPowerTap Technology allows instant adjustment between max output and dimmed powerSettings include full strength in proximity and distance modes, dimming, strobe, red night-vision and digital lock modeIntegrated battery meter display shows % of power remainingBrightness Memory allows you to turn the light on and off at a chosen brightness without reverting to default settingMultifaceted optical efficiency lens technologyRed night vision has dimming and strobe modes and activates without cycling through the white modeDigital lock mode feature safeguards against accidental use when stored in a pack or pocketWeight: 73g