From the ManufacturerSunlite compact fluorescent plug-in lamps are used with external electronic ballasts. They are available in a wide range of sizes, wattages, color temperatures and pin configurations. This Sunlite 9-watt compact fluorescent plug-in 4-pin light bulb offers 525 lumens of light output and a color rendering index of 80. It has an average lamp life of 10000 hours. The 3500K color temperature produces a soft white light similar to standard incandescent bulbs. The PLD9/SP35K fits a G23-2 2-Pin socket.