SK3012 AF Power amp, regulator, PNP Germanium, TO-36.  In original RCA packaging.

Replaces  2N173, 2N174, 2N174A, 2N174RED, 2N441, 2N441BLU, 2N442, 2N443, 2N574, 2N574A, 2N575, 2N575A, 2N1099, 2N1100, 2N1157, 2N1157A, 2N1202, 2N1203, 2N1261, 2N1262, 2N1263, 2N1358, 2N1358A, 2N1358M, 2N1412, 2N1433, 2N1434, 2N1435, 2N1567, 2N1568, 2N1569, 2N1970, 2N1980, 2N1981, 2N1982, 2N2075, 2N2075A, 2N2076, 2N2076A, 2N2077, 2N2077A, 2N2078, 2N2078A, 2N2079, 2N2079A, 2N2080, 2N2080A, 2N2081, 2N2081A, 2N2082, 2N2082A, 2N2155, 2N2155A, 2N2159, 2N2159A, 2N2210, 2N2266, 2N2267, 2N2268, 2N2269, 2N2379, 2N2490, 2N2491, 2N2492, 2N2493, 2N3311, 2N3312, 2N3313, 2N3314, 2N3315, 2N3316