Our Sunshine Universal T8/T12 LED tubes replace 48-inch T81-inch diameterand T121.5 inch diameterfluorescent bulbs using the existing fixture and electronic ballast. It's slim size fits in the same fixtures as traditional 48-inch T8 and T12 fluorescent bulbs. Why make the switch to LED? Our LED tubes provide long 16-year life based on six hours use per day, so you'll replace less often. They use less energy than a 32-Watt T8 or 40-Watt T12 fluorescent tube with nearly the same light output helping you save money on energy. And, they're mercury free. Use Cool White Universal LED tubes in basements, garages and commercial applications like warehouses and industrial buildings to provide a cool neutral white light.?