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Sylvania SD990 pentode tube
Sylvania SD990 pentode tube

Sylvania SD990 pentode tube

Date1925-1930
Inventory NumberVT1003
ClassificationVacuum Tube
Maker Sylvania Products Company 1924 - 1931
Maker Sylvania 1924-present
Cultural Region
    Place of Origin
      Dimensions3.4 × 1 × 1 cm (1 5/16 × 3/8 × 3/8 in.)
      Signedin green ink on glass: SYLVANIA / SD-990 / MADE IN USA in green ink on glass: [Sylvania S logo] in green ink on glass: KK9
      Curatorial Remarksnot in databases-check number on tube
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