ALZO 45W Joyous Light Full Spectrum CFL Light Bulb 5500K, 2800 Lumens, 120V, Pack of 4, Daylight White Light Crisp, bright white light ideal for reading and tasks that require visual accuracy; CFL bulb has natural daylight balanced color temperature of 5500K; pack of 4 This is a large bulb that might not fit standard household lamps, see diagram above; dimensions: length: 7 inches; Width (Diameter): 3 inches; fits all medium-base E27/E26 sockets Good for starting plant growth; generates very little heat; all ALZO Joyous light bulbs are flicker-free Energy saving, uses about 1/4 of the energy of a comparable Tungsten bulb, with 2800 Lumens output at 120V; about 8,000 hours bulb life Important: ALZO CFL bulb life is based on the bulb in an open air upright orientation. When ALZO bulbs are installed in fixtures that lack adequate ventilation, the life of the bulb will be reduced