Amperex Pinched Waist 6922 vacuum tube.This holy grail pinched waist tube is made in USA in late 1950's. Labeled as Amperex USN (US Navy) or PQ. I have several available for matched sets and they are all low noise ones. Measures very strong on my Calibrated Hickok 539C tube tester. No shorts, leakage, or gas. Also, tested in my preamp and work perfectly. Individual test measurement results for each tube will be provided to you upon your order. Full money back guarantee! USPS Priority mail shipping with tracking within US will be $9. Payment by check or money order (no Paypal please). Local pickup with cash is welcome.
| 
