What is the difference between T8 and T10 bulbs?
The T8, T10 and T12 tubes are mainly difference in the diameter of the tube. The main difference is in size…the T8 is one inch in diameter and everything else is divisible by that number: T5 = 5/8 inch, T6 = 6/8 inch, T8 = 1 inch, T10 = 1.25 inches (10/8), T12 = 1.5 inches in diameter (12/8). via