T9 circular triphosphor flourescent tubes with 29mm tube diameter this t9 has an average life of 10 000 hours t9 circular lamps are available in colours warm white 840 and cool white 830 40w t9 circular tubes have a g10q 4 pin cap these circular tubes are boxed in 12s general characteristics wattage w 40 voltage v 230 capbase g10q bulb shape circular bulb diameter mm 409mm colour rendering index cri ra 82 rated life l7 h 10000 dimming capability yes