Amperex Holland "Pinched Waist" 6922
All three tubes above are early "pinched waist" 6922 made by Amperex Holland.
 
The left one is a used one with only very little marking left. It is very hard to tell what the original marking is but it may be Valvo. There is no etched code on the glass envelope but there is the remain of a two-rows six digit code. The first row cannot be read any more. But the 2nd row looks something a triangle followed by "8K".
 
The one in the middle is a NOS with Amperex Holland marking and Amperex Holland etched code. (2nd row started with a triangle)
 
The one on the left is another NOS with Amperex USA marking and Amperex USA etched code (2nd row started wth *)
 
It should be easy to tell that even when all 3 have the same D-shape getter. The getter support of the left one is very different from the other 2. An earlier model?

This is a close-up of the getter support structure :


[Createyourownwebsiteathomestead.deja.com!]