NOS Date Matched Pair NU National Union USA 39/44 Engraved rtl Vacuum Tubes

Tube Type / Number: 39/44
Actual Brand*: NU National Union
Printed Brand: NU
Quantity of Tubes: Date Code Matched Pair
Plate Construction: Wide Mesh
Getter Construction: Thimble
Country of Manufacture: USA
Visible Date Codes: T & T
Lettering Condition: 90 Percent
Year Made:
Mica Spacers: 2
Smoked Glass? No
Engraved Base? Yes
Boxes Included? 2 Boxes - Both NOT Original
Notes: ST, 1 Tube Rattles, Sawblade Mica

Gm Test Results: 51 & 56
Minimum Good Value: 25
NOS Test Value: 41
Life Calculation: 100+% (where 65% = fail)

Tests as NOS?: Yes
True NOS?*: No

** Please note, many tubes will test NOS but will actually have a few hours of use on them. A truly NOS tube will have excellent getter flashing condition, no dirt/grime, usually in the original box, and no filament deposits. If a tube is listed  as "tests NOS" but is listed as "not True NOS" please expect the tube to have a small amount of use *

All tubes have been tested using only the best tube testers. We have a large fleet of tube testers, and every single one of them has been calibrated within the last year by industry experts. We mainly use the Hickok TV-7D/U, but occasionally we may use a Hickok 539, 533A, or 600A.