Si-N 1000V / 450V 20A 175W hFE β>80 23A / TO-3, Power Transistor for Military & Aviation Aplication, CE/ISO Certification. SGS Thomson. Cross Reference: 4917070-00 49170-7000 4917070 S49170 SG49170 SGS4917070, equivalent: BU326 BUX48A.