Sunlite 05810-su fc22t5/sp841 22w fluorescent t5 circline bulb, 2gx13, cool white the fluorescent 22 watt 4,100k cool white t5 circline features a 2gx13 base, provides a light output of 1,900 lumens at a color rendering index (cri) of 82 and can last an average of 10,000 hours.