For sale 2 tubes U415 Zenith NOS NIB with own carton box = re134
tube type triode dht preamp 4 volt heater
selcted for the Royal Air Force
data 1939
tested strong with 4 volt heater & 150 volt on anode
test results Ia = 30mA & 26mA (reference good at 18mA)
tested also on tube tester Avo VCM163 as per labels on pictures
great vintage tubes test strong selected
full life
hard to find