Fluorescent T5 Circline High Performance Lamp, Designation: FC55T5/Ho/830, 55 WTT, T5 Shape, 2GX13 2GX13 (4-Pin) Base, 12000 HR, Lumens: 4200 LM Initial, Lumens: 4000 LM Mean, 3000 Deg K Color Temperature, Warm White 82 Cri, 12 In Length, 5/8 In Diameter