A flashlight is a hand-held portable electric-powered source of light. A simple enough question with a simple enough answer. This small device is usually powered by a battery which produces energy to illuminate the light source of the flashlight. Over the course of the years, flashlights used incandescent bulbs that did produce a lot of light, but at the cost of energy efficiency and excess heat. This all changed with the invention of the LED (light-emitting diode) bulb which not only cuts energy costs by a huge factor, but also made flashlights last longer, light up further, weigh less and burn cooler and brighter than ever before.