These Candelabra E12 mini screw bulbs use one single piece of high power 2W LED emitter to match the output of a typical 20W Candelabra incandescent bulb. They last 50,000 hours which is 50X the average incandescent light bulb life. Buy once, and you may never have to replace them again in your lifetime. That's why we call them "EverBulb".