(2) Sylvania 12BH7A Tubes Matched Codes Gray Plates O Getter Tests NOS Amplitrex
(2) Sylvania 12BH7A Vacuum Tubes Matched Codes Long Gray Plates O Getters. Tested on an Amplitrex AT1000.
RCA 12BH7 GRAY PLATE HALO GETTER TEST NOS IN BOX VINTAGE 1960’S
Average NOS test results for 12BH7's 2380 microhmos on the Hickok 600A. Tube 1.2500/2200Gm Shorts, Gas, Grid Emissions-None.