231D Western Electric NOS 1953 (1.6ma)
5691 RCA Red Base Black Plates used 1948 (2.2/2.4ma) (Gm=62% and 75%)
6B7 Raytheon NOS 1950 era (2 in stock)
6B7 RCA Delco NOS 1940's (1 in stock)
6B7 RCA Emerson NOS 1940's
6B7 Sylvania engraved base tests like new 1930's
6D6 Sylvania NOS 1940's
6D6 Sylvania NOS small 1/8" glass chip inside tube at bottom
6D6 Sylvania sealed NOS 1940's (5 in stock)
6SQ7GT Fonoco by Sylvania used/strong 1951 (1.1ma and Gm=1100)
6V6GT GE Delco used/good crack in base 1952 (36ma)