PTT0 (PTT0)

I have three tubes PTT 0. The type number is printed on the bulb. The base shows the type number R88. IIt seems that PTT 0 and R 88 are identical. One one specific tube, the typenumber reads PTT 0 and below that PTT144. I never heard of that tube .

 

 

I have seen that for PTT 0 and R 88 are seperate tube pages, yet they seem to be identical apart from the white ceramic support in the R 88.

Are my assumptions coorect ?

To thank the Author because you find the post helpful or well done.