2SB1557 TOSHIBA Silicon PNP Darlington Power Transistor, 
Vcbo -140V, Ic -7A, Tc 25°C 70W, 30MHz, hFE1 10000..30000, 
Case type: TO-3PI (MT100),

Marking: B1557.O  
BCE 

Complementary NPN 2SD2386