The X5 combines small size and bright, uniform illumination that, as far as I know, is simply not achievable in flashlights that use incandescent bulbs. The five recessed LED bulbs in the X5 put out 82 lumens at under four watts, and they won"t drain your batteries nearly as fast as an incandescent bulb (the two 123A lithium batteries should last around 20 hours).This flashlight is unlikely to break if you drop it: The body is made of anodized aerospace-grade aluminum, and the optical system is protected by a stainless steel head. Plus, LEDs are much less likely to break than incandescent bulbs. As anyone who"s found themselves in a pitch-black crawl space with a nonfunctioning flashlight will tell you, durability is a good thing.The X5 features a three-mode switch cap, which enables the user to turn it on and off without flipping it around from an under- to overhand grip. As we mentioned above, the light projected by the X5 is exceptionally uniform from the edge of the beam to the center, making it unnecessary to fiddle with a focus mechanism to get the beam just the way you want it. This flashlight also has a remarkably strong beam for its size, and it maintains its integrity and focus extremely well at distance (the manufacturer gives an "effective range" of up to 150 feet). Two 123A lithium batteries included.--Josh DettweilerWhat"s in the Box Flashlight, two 123A lithium batteries