[kx250rider]

I remember reading someplace, that a second letter in the sequence (in CRTs following bottle diameter) meant it was a better design tube. (i.e. 21YP4 vs. 21FEP4, etc)

So the string for a 21AXP22A would be:

21 ____________ AX________________________P22___________A
Bottle size_______Tube model Type_____________Phosphor type__"A" = aluminized

Charles