Tested Pair of Type 33 National Union Audio Receiver Radio Power Vacuum Tubes 

Country of origin: USA

Production era: Estimate 1940s

Model:  33

Manufacturer:  National Union

Type: power

Plates: silver ribbed     

Spacers: two

Base type:  UY 5 pin

Getter frame: dimpled foil

Getter flash: circular side

Filament: hanging V

Glass: clear 

Stencils:  very good

Condition:  excellent, same configuration

Usage (estimate):  minimal

Cartons: NA

Quantity:  2

Please review the photos for more detail

Test results:

       Excellent strong balanced test results for Gm: 1.45 and 1.50

       For Gm, the suggested minimum is:  .9

Shorts: None detected

For testing, a calibrated Triplett 3444A tester was used

Compatibility: Suitable for vintage tube-based equipment, ideal for use in audio amplifiers, power amps, and general tube equipment

The tubes 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