Normande Lighting NFS13W2P 13W Daylight Bulb The 13W daylight circular bulb is equivalent in brightness to a 40W incandescent light bulb and saves energy The 13W daylight bulb provides better contrast and less eye strain for a sharper and clear image The 13W daylight bulb is long lasting and energy efficient saving you valuable dollars The daylight bulb last up to 10,000 hours and provides a positive step for the environment The daylight bulb offers a color temperature of 6000 Kelvin (plus or minus 500K). The higher the Kelvin temperature the closer you are to natural daylight