Buy 12ax7 tube

*zaerix cv492(not zaeux)

What is this?!
https://drive.google.com/file/d/1SxRg18P1ipUnBRWOjlHb0pC-gC1aVMfG/view?usp=drivesdk  

Another vote for Telefunkens. Years ago I found them too bright, preferred Amperex, Mullard, RCA. But I came across a number of Dynaco and Fisher units, too trashed to rebuild, but the tubes were okay. Telefunkens. I have about 40. My preamp takes 4 x 12AX7 and 4 x 12AU7. The Telefunkens are 40, maybe 50 years old, with countless hours on them — but they're dead-silent, tonally rich and true, ravishing midrange, and I hear no brightness: maybe age mellowed them.

The 12AU7s are NOS Tung-Sols or NOS JAN GE's — they're the weak partners in the team. Man was I surprised. Maybe they need burn-in, I hope so.

Sorry I can't comment on new production; I haven't needed them. But I will, so I follow these discussions closely. Thanks all, for the informed opinions.

OP... CEI was a distributor that sold quality tubes made by other manufacturers. 

Zaerix relabeled other manufacturers' tubes. I found a couple in used components.
https://www.18watt.com/viewtopic.php?t=23510

Buying tubes for $20 without etched factory codes or test results is a shot in the dark. Even if it sounds good, it may not last long. And with rebadged tubes and no description, you won't know their sonic signature.  
My advice, spend some money and buy from a reputable dealer who posts tube measurements and offers exchanges. There are many good NOS tubes for $50.

Is it rca?

https://drive.google.com/file/d/1SVg-jJ7my4F9PCkwg43CtHwjm4B_x2n8/view?usp=drivesdk

@bimasta, I love NOS Tung-Sol AU12's. I find them to have tonal purity, good extension, and a slight but pleasant tube bloom.