The Mullard GZ34 is known to the be the best of the best of all 5AR4 variants. We have a single Mullard for sale, this was manufactured at the Black Burn factory in England.
All tubes are tested on a AT1000 computerized tube tester, rectifiers are tested at real voltages and are balanced based on voltage drop.
Please be aware that vintage vacuum tubes are antiques and carry no guarantee or warranty. We provide a sheet explaining what you purchased, your test results for your tubes, and if need be can provide photographs of the tube on the tube tester before we pack and ship them.