WX12

I would just like to point out that the 864 tube is often used as a substitute for the WX12 tube.  the differences between the WX12 and 864 are very small, but the WX12 is in much shorter supply than the 864.  Therefore, it is generally much cheaper to use an 864 tube in place of a WX12.  I am not sure why these two tubes are not shown as substitutes for one another on this website.   

nN wonder, the substitution was not yet shown since nobody had us informed yet!

You are the first, and consequently I checked and introduced the cross reference.

We are building up from the info brought in by the members.

Anyway: Thanks for the hint!