T-5, T-8, T-12, etc

[PixSell]

Does anyone know where (have a link to) I could find a good description of what all the "T-(numbers) mean for florescent lights & bulbs?

T-5, T-8, T-12, etc?

Thanks, Chris

[Brent F]

The number refers to how many eighths of an inch the tube is in diameter, so a T5 is 5/8ths of an inch and a T8 is 8/8ths of an inch