A 40 watt t5 circular fluorescent tube this t5 circular lamp has an average life of 5 000 hours and has a b class energy efficiency rating t5 circular lamps are available in colours warm white 830 cool white 840 general characteristics wattage w 40 voltage v 230 lumens lm 3200 capbase 2gx13 bulb shape circular bulb diameter mm 293mm colour rendering index cri ra 82 rated life l7 h 12000 dimming capability yes please note these lamps should be replaced l