OptoLight Compact Fluorescent 42W Bulb with Light output of 150w Incandescent the bulb itself is larger than a standard light bulb. it may not fit in many indor fixtures 6.875 x 2.875 inches great for porch lights Dimensions 6 7/8 x 2 7/8 inches. Make sure to measure your light fixtures needs 2650 Lumens Average life - 10,000 hours