Cree XM-L T6 LED 1800-Lumens Bicycle Headlight 3 Mode Rechargeable Bike Light +battery+Charger+head strap Three gears design: high/low/with flash, highlighting the 1800 lumens navigation time four hours, low light 400 lumens 8 hours Waterproof,can ride in rainy day can be used as the head lamp,useful for Daily mountaineering, 4800 mah add protection board lithium electricity ,with high capacity, Constant pressure current, from beginning to end all the same high brightness, has no electricity from will put off, and not like a step-down circuit as can slowly going down.