20 watt T4 dimmable spiral soft white Compact Fluorescent Bulb at 2700 Kelvin, replaces a 100 watt incandescent bulb. Uses 75 percent less energy than a 75 watt incandescent. Lasts about 10,000 hours, more than six times that of standard 1500-hour incandescents. Ideal for ambient lighting, this 5" long bulb quickly pays for itself in lower electric bills, without sacrificing the soft glow associated with incandescent lamps. Bulb's medium base fits all standard sockets.