Details
New old stock 9 pin miniature twin triode. Various brands. ECC88 is the European designation.
NSN/FSN = 5960000527654, 5960004016705, 5960004658344, 5960005239725, 5960006790016, 5960006905705, 5960006909991, 5960007153894, 5960007934182, 5960008086931, 5960008182134, 5960008381360 (pair), 5960008800457, 5960009194568, 5960009316987
HP/Agilent Number = 1932-0022, 1932-0035, 1932-0061, 5080-0410, 5080-0411, 5080-0432, 5080-0439
Tektronix Number = 154-0187-00