LEDs (light-emitting diodes) can be significantly more efficient at lower power levels and so use less battery energy than ordinary lightbulbs. Resulting in a longer battery life, in some cases hundreds of hours, although the LED efficiency advantage diminishes at higher power levels. LEDs also survive sharp blows that often break conventional lightbulbs.
Flashlights that use LEDs instead of conventional lightbulbs have become available. LED flashlights with power and running time better than some incandescent lights. The first Luxeon LED flashlight was the Arc LS in 2001.
LED flashlights are often electronically regulated to maintain constant light output as the batteries fade. By contrast a non-regulated flashlight becomes progressively dimmer, sometimes spending much of the total running time below 50 percent brightness level. Therefore some mini led flashlights are produced. These mini led flashlights are small, bright, low price, easy to operate. Mini led flashlights need a little powers, so their lives are much longer.
A common misconception about LED-based flashlights is that they generate no heat. While lower-power LED flashlights generate little heat, more powerful LED lights do generate significant amounts of heat – although not as radiant energy, as the semiconductor junction inherently dissipates heat. For this reason higher-powered LED flashlights usually have aluminum bodies and can become quite warm during use. For example, strong Beam Flashlights have more powerful LED lights and significant amounts of heat. But their LED bulbs use less energy than regular bulbs and the batteries will last longer. Its solid aluminum casing is shockproof and virtually indestructible. Very few high-output LED flashlights use a plastic body due to plastic's being a thermal insulator rather than a conductor. Plastic Led Flashlights are made of ABS plastic. Anti-shock switch, non clip with comfortable plastic skin of the LED flashlights. Rubber Flashlights are made of rugged ABS plastic with rubber grip or heavy-duty rubber case. Its main feature is anti-shock and weatherproof. End strap of rubber flashlight for easy carrying. It fits conveniently into a backpack, a tackle box, a glove compartment, or can be clipped to a pocket, or carried by the wrist loop.
References
http://en.wikipedia.org/wiki/Flashlight#LED
http://www.led-flashlite.com/product/rubber-flashlight/index.htm