Hickok 539C tested and matched. Near perfectly matched for both GM and MA (Current). Matching date codes also. To ensure maximum performance and longevity make pins are clean and tube glass is free from finger prints/dirt when replacing tubes.
Rectifier Vacuum Tube. Possibly unused new tube! Made in USA. ____ ______. where minimum good value is 54.
"Made in Great Britain". Firm base, excellent silvering. Tube tests at 160-160 where pass/fail is 80. This tube tests in the range of new in box Mullard 5AR4/GZ34 tubes that I have had.