On flourescent lighting, the number after the "T" indicates the diameter of the bulb in 1/8" increments. Therefor a T5 bulb is 5/8" diameter, a T8 is 8/8" or 1" diameter, a T12 is 1.5" diameter.<a href=showthread.php?s=&postid=9895730#post9895730 target=_blank>Originally posted</a> by flasher1
Whats the difference between t5's and t8's???