“This hybrid LED bulb replaces an older CFL and compact ballast lighting system in an older Sharper Image round make-up mirror. I purchased it as an alternate or spare to another bulb I also found at ProLighting. Both work well and fit perfectly. If and when the other one gives up the ghost, I will install this one into the existing socket. It is the right size and doesn't require a ballast of any kind. This type of "hybrid" bulb is the perfect way to salvage an older light fixture!”