EarthTronics CF09CW1BT2 9-Watt 4100K Micro Spiral Compact Florescent Light Bulb, Cool White, 12-Pack Save money and the earth-this bulb only uses 9-Watts of power and outputs the equivalent light of a 40-Watts incandescent bulb Small, compact design, fits where standard bulbs are used 12000 hour average rated life means you'll almost never have to change bulbs Utilizes an advanced electronic ballast so the bulb reaches full brightness quickly 7 year limited warranty based on normal residential usage (3 hours average usage per day/7 days per week)