(!!!!) (SINGLE) 7581A GE tan bases green printing 1960 era (73.5ma)
7581 Tungsol brown base used/75% 1964 (52.5ma)
7581A GE branded RCA NOS 1974 (59.5ma)
7581A GE NOS 1979 (76ma)
7581A GE NOS 1979 (87ma)
