37 Philco Balloon used/good 1930 era (6.5ma)
42 Philco balloon engraved base used/good 1930 era (31ma)
46 RCA NOS 1940's (60.4ma Gm=3210)
46 Sylvania NOS 1940's (52ma Gm=2950)
46=VT-63 Tungsol NOS 1940's (62ma Gm=3350)
51 Arcturus Blue Balloon used/very good 1930's (46/26)
551 Arcturus Blue Balloon used/very good 1930's (43/26)
56 RCA Balloon engraved base black plate tests like new 1930's (4.7ma)
71A RCA Cunningham Radiotron used/tests like new 1936 (24ma)
71A RCA Radiotron Balloon used/good 1930's (21ma)
874=US Navy CRC 38274 RCA Radiotron Balloon tests like new 1930's
C324 Cunningham Balloon used/good 1930's (2.8ma Gm=700)
C324 Cunningham Balloon used/good 1930's (3.5ma Gm=800)
Deforest Audion Isolantite base display tube (single)
Deforest Audion metal base display tube 1920's (single)
NY-224 National Union Balloon used/good 1930's (38/25) (3.3ma Gm=800)
UX-226 RCA Radiotron balloon used/good 1920's (3.7ma Gm=900)
UX-874 Radiotron Balloon tests like new 1930 era
UY-224 RCA Balloon used/good 1930's (37/25) (3.0ma Gm=700)