Sunlite 21W 34 inch Warm White 3000K T5 Fluorescent Tube Bulb - F21T5/830 Sunlites Ultra 5 Fluorescent lamps were designed to provide the greatest lumen package in the shortest possible linear tube. Thus the Ultra 5 series of lamps provides energy efficiency, high color rendition, optical control and improved lumen maintenance in one of the slimmest linear fluorescent lamps on the market today. Used by psychedelic shops for lighting fluorescent posters, displays, etc Sunlite 21W 34 inch Warm White 3000K T5 Fluorescent Tube Bulb - F21T5/830 Base: G5, Rated Life (hours): 20000