48" T8/T12, 40 W, T8 Tube, 15 W, Bright White, 6/CartonGE's T8 LED tubes replace 48 inch T81 inch diameterfluorescent bulbs using the existing fixture and electronic ballast. It's slim size fits in the same fixtures as traditional 48 inch T8 fluorescent bulbs. Why make the switch to LED? GE's LED tubes are rated to last 36,000 hours. They provide long 16 year life based on six hours use per day, so you'll replace less often.