One Tested 5Z3 National Union Audio Receiver Rectifier Vacuum Tube 

Country of origin: USA

Production era: 1940s

Model: 5Z3

Manufacturer: National Union

Type:   Rectifier

Plate type: black ribbed

Base type: UX 4 pin

Spacers: One 

Filaments: hanging V

Getter frame: rectangle wire

Getter flash: base

Glass: Clear

Stencils: very good

Condition: excellent

Original carton: NA  

Usage: minimal

Quantity: 1

Please review the photos for more detail

Test results:

Strong balanced NOS results for Emissions: 44 / 43

For Emissions, the suggested minimum value: 28  

Shorts: None detected

For testing, a calibrated Triplett 3444A tester was used

Compatibility: Suitable for vintage tube-based equipment ideal for use in tube amplifier power supplies and vintage audio / test equipment

The tube will be carefully packed to ensure safe shipping

Estimated delivery time within the USA is 3 to 7 business days

Standard shipping service is US Postal 1st class

Shipping is combined when applicable

Please feel free to contact us if you require any additional information