(!!!!) (Best Overall Single) 50 RCA Cunningham engraved base NOS ST-19 around 1940 (61.5ma) (strong Ma and Gm)
(!!!) (Best Balloon 50) 450=50 Sparton Balloon tests like new 1930 era (61.5ma) (High mA and Gm) (rare 50)
(!!!) (Recomended Balloon 50) CX-350 Cunningham Balloon used/good 1930 era - very good condition (44.2ma) (rare 50)
4-Pin EF Johnson (122-224-1) ceramic wafer socket NOS (UX-4) (6 in stock) (300B, 10Y, 2A3, 45, 50, 26)
