I converted all 39 florescent fixtures in my main shop to LEDs. I used one "bulb" per fixture and got more light than two 40 watt bulbs for the cost of 22 watts. I bought several cases on Amazon. The fixtures had to be rewired to provide "hot" and neutral at one end and nothing at the other (support only). I left the ballasts in place, just not hooked up-about 5 minutes per fixture to rewire.
I love them!
Mike LeFevre
SGL 6-pack T8 LED Shop Light Tube 48W Equivalent 4ft, Single-Ended Power 5000K Daylight White, Frosted Cover, 2310 Lumens, G13 Lighting Fixtures, UL-Listed & DLC-Qualified