This Nite Ize LED Upgrade Kit improves light quality, increases battery life, and transforms your old incandescent C or D cell flashlight into a newly efficient, economical, and long-lasting tool. In a snap.<br>The Nite Ize LED Upgrade Kit converts most C & D (2-6 cell PR style flange) incandescent flashlights into bright, long lasting (100,000 hour) LED flashlights. It's as easy as replacing the bulb - 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 LED technology also ensures a much longer battery life, making it not only a useful, versatile improvement, but an environmentally-friendly & pocketbook-friendly one as well.