This part is a kind of semiconductor called SSF7509B.

Function of this product has MOSFET.

Manufacturers : Silikron

Image and pinout :

Some of the text within the PDF file :

Main Product Characteristics: VDSS RDS(on) 70V 5.3mΩ(typ.) ID 100A Features and Benefits: TO-220  Advanced MOSFET process technology  Special designed for PWM, load switching and general purpose applications  Ultra low on-resistance with low gate charge  Fast switching and reverse body recovery  175℃ operating temperature SSF7509B Marking and Pin Assignment Schematic Diagram Description: It utilizes the latest processing techniques to achieve the high cell density and reduces the on-resistance with high repetitive avalanche rating. These features combine to make this design an extremely efficient and reliable device for use in power switching application and a wide variety of other applications. Absolute Max Rating: Symbol ID @ TC = 25°C ID @ TC = 100°C IDM [ ... ]

SSF7509B PDF Datasheet Download