The Nite Ize 1 Watt LED Upgrade Bulb converts any C & D (2-6 cell PR style flange) incandescent flashlight into a super-bright, long lasting (50,000 hour) L.E.D. light. Its as easy as replacing the bulband instantly, your flashlight will emit a pure white (as opposed to the incandescent dull yellow) light, in spot to flood focus. Self-adjusting for all capacity levels, this efficient L.E.D. technology also conserves battery use, making it not only a useful, versatile improvement, but an environmentally-friendly one as well.