The current bulb’s ID is F8T5/D. What does the D mean? I ask because I saw a bulb today that is F8T5ww and I’m wondering if the D means something important -meaning that anything other than that specific code isn’t going to work in the fixture - or if perhaps it’s just something to help identify the manufacturer… Anyone know?
That’s a Fluoresent 8-watt T5 size Daylight color-balanced bulb. WW would be some sort of white. In other words, any F8T5 bulb will work in your fixture, it just may not match the original color balance.
Expanding on what QED posted, the more popular fluorescent lamps are given an alpha designator which relates to their color, as measured in degrees Kelvin.
WW = Warm White = 3000K
CW = Cool White = 4100K
LW = Lite White = 4200K
D = Daylight = 6500K
The higher the temperature, the cooler the appearance of the light. You can also refer to the CRI or Color Rendering Index of a lamp. The higher the number, the truer the color on a scale of 0-100.