DAY LIGHT 55 Watts FLUORESCENT (CFL) BULB for DIGITAL PHOTOGRAPHY 55 Watts (250 Watts incandescent) CFL bulb; 3600 Lumens; daylight 5000K Measured Color Rendering Index (CRI) &gt; 84;Operating Temperature cool ("flicker free"); no color correction needed; Hours of life 8,000 hours Energy Star Compliant, screw into standard sockets Bulb measurements 8.39" length (L), 4.45" diameter (D); Base measurements 4.06" length (H), 2.95" width (W) Certificate UL/CUL/FCC