[Amps] VTX-X118 Tetrode mytery tube?

[KL7RA]

Originally the new AP8410 used the Eimac 4CX1000A tubes but they made a
switch to the VTX-X118. Seem to be a mystery tube, can't find the spec sheet
and never heard of them.

Anyone know anything about this tube? My guess is Alpha used the 4CX1000A
but got them with a higher grid rating?  It looks like this tube number is an Alpha
part number to me. 

73 Rich KL7RA   Alpha amp owner 

>From Alpha:
The amplifier uses the Alpha Power brand VTX-X118 tubes, a ceramic, external-anode,
 indirectly heated tetrode that, unlike the excellent Eimac 4CX1000A, is qualified to handle 
the grid current that might be experienced in the AP8410.