this is the old coding system
V is the flux. It is average. U is the lowest, continued to V then W then X
3 is the color, it is the best on the old days. It should be pretty white. But the range is wide, so it can as white as WO or can be VO or YO
T is the Vf. I think this is the lowest Vf you can get for a white 5W lux
the rest just general name.