Series lamps have an increased cri due to the use of tri-phosphors (rare earth phosphors).
Sunlite 30390-su f35t5/841 35w fluorescent t5 bulb, mini bi-pin, cool white the fluorescent 35 watt 4,100k cool white t5 high performance straight tube features a mini bi-pin base, provides a light output of 3,100 lumens at a color rendering index (cri) of 82 and can last an average of 20,000 hours. Sunlite® F35T5/841 35W Fluorescent T5 Bulb, Mini Bi-Pin, Cool White These series lamps offer superior quality of lighting, increased energy efficiencies, and extend life.. Tri-phosphors also increase the lumens/watt output of the lamp.