LED flashlight. In recent years, high-power white light emitting diodes (LEDs) reached consumer price levels and found their use in flashlights. Compared to conventional lightbulbs, LEDs are more efficient, have longer battery lifetime and are more durable. White LEDs are typically based on blue LEDs (InGaN, indium gallium nitride) coated with doped YAG (yttrium aluminum garnet) crystals, which act as a phosphor, down-converting part of the blue radiation to a broad spectrum centered in the yellow. The resulting spectral mix has the appearance of white light to the human eye. Shown here is a 1-Watt LED flashlight sold in the US by Energizer. Oct 2007.