Auction is one Rare Prototype ( 2 x OO Getter ) EF802 Military Tubes Telefunken Diamond Bottom NOS NIB 1959'y
(~EF800, very very close, the same pinout, but without anode shield and less capacitances)
Very Low Noise Microphone Pentode.
''
Before the measurements, the tubes were preheated with a voltage of 4V, 5V and 6.3 V.