The double twin tube CFL is an energy efficient alternative to traditional incandescent. These bulbs last up to 10 times longer and use 75 percent less energy than an equivalent incandescent light bulb with the same light output. These 4-pin replacement CFLs are for general illumination applications with fixtures that have electronic and dimming ballasts-everything from recessed or down lights to wall sconces and outdoor lights. These light bulbs contain mercury. Dispose of according to local, state or federal laws. CFLs save up to 75 percent energy compared to incandescent light bulbsLong life for reduced maintenance costs4-pin CFLs are dimmable when used with electronic dimming ballasts