These tubes came from the factory many years ago- a friend worked there and was given them, we have had them In our collection now for 4+ years. One of our favorites- ZERO NOISE. Three micas- closed getter that resembles a top hat.

Would be excellent in any sensitive to noise preamp

RETURNS ARE NOT ACCEPTED BECAUSE YOUR TESTER SAYS SOMETHING DIFFERENT THAN MINE. If you don?t like the sound of a tube, so long as it is still in the same condition as arrived message me and I?ll work with you