New NL5557/FG17 High Sensitivity Thyratron High Frequency Machine Tube. GZ37 53KU GZ37 CV378 Mullard rectifier vacuum tube Ampltrex tested #729001. Amplitrex AT1000 Advance Digital Tube Tester, Hickok 752a tube tester, AVO Type 160.
New NL5557/FG17 High Sensitivity Thyratron High Frequency Machine Tube. GZ37 53KU GZ37 CV378 Mullard rectifier vacuum tube Ampltrex tested #729001. Amplitrex AT1000 Advance Digital Tube Tester, Hickok 752a tube tester, AVO Type 160.