3-500Z's - is the 500ZG the way to go ?

[K8DO at aol.com]

Hi Dave... 
Possibly PRIDE is a private brand labeled Svetlana tube... I know that RF
PARTS (619-744-0700) sells the Svetlana tubes with their name imprinted on
them as a brand label.... They get $229.95 for a matched set of two
3-500ZG...

Addendum:
I received a private message from overseas stating that the 500ZGs only last
a few hours in a Kenwood TL922... I have no details on the AC regulation,
filament voltages, drive levels, etc. so I mention this but have no
opinion...

Denny