40w T9 Circular Tube. The thickness is denoted by T9 or T5 this is the thickness of the glass tube itself. The T9 tubes have four Pins on the inside of the glass ring. Circular Bulb.
Bell 60w T9 Circular Fluorescent Tube - 29mm tube diameter (COOL White, 4000k)
Bell 60w T9 Circular Fluorescent Tube - 29mm tube diameter (Warm White, 3000k)
GE 40W 4000k Circular Fluorescent Tube 2GX13 3300lm
2 x 40W T9 Cool White Crompton Circular Fluorescent tube Round FC40W840 40 Watt
CIRCULAR FLUORESCENT TUBE T9 40W COOL WHITE 4000K
40 Watt Round/Circular 40W T9 Fluorescent Tube Light Bulb 4000K Cool White
