13 watt spiral compact fluorescent cool white light bulb at 4100 Kelvin is great for your task lighting. Medium base fits all standard sockets. Uses 75 percent less energy than equivalent 75 watt incandescent and at 10,000 hours, lasts up to 10 times longer than the incandescent. By replacing a single incandescent with a compact fluorescent, you can keep a half ton of CO2 out of the atmosphere over the life of the bulb. Compact fluorescent bulb is Energy Star Approved.