T5 grow lights

T5 lamps have a diameter equal to 5 times an eighth of an inch, or 5/8″. These lamps are approximately 40% smaller than T8 lamps, which are one inch in diameter, and almost 60% smaller than T12 lamps, which are 1½” in diameter. Figure 1 shows diagrams of lamp ends of T5, T8, and T12 lamps.