A flashlight is only as good as its LEDs. The Core Lumen Flashlights is fitted with industry leading CREE LED bulbs that will last the lifetime of the product. A momentary on switch allows you to get a quick burst of light by pressing the power button down half way without turning the flashlight fully on. To toggle quickly between the three modes just half press the power button repeatedly until you find your desired light output. Requires 2AA batteries that are included for your convenience. When it is time to change the batteries, please note that it is important to never mix old and new batteries. These flashlights are built with high quality aircraft grade aluminum to handle real, everyday usage. It can withstand a fall onto a concrete surface from up to a meter high and will still function properly after being exposed to rain and water (but should not be fully submersed).