Details
Used old stock 9 pin miniature sharp cutoff pentode. Various brands.
NSN/FSN = 5960000238976 (pair), 5960000528984, 5960002957707, 5960002963384, 5960004362944, 5960005382363, 5960005533662, 5960005781602, 5960006048890, 5960006983774, 5960007835920 (pair), 5960008381359 (pair), 5960008554776 (pair), 5960008940131
Tektronix Number = 154-0047-00