This part is a kind of semiconductor called SSF7509.

Function of this product has MOSFET.

Manufacturers : Silikron

Image and pinout :

Some of the text within the PDF file :

SSF7509 Main Product Characteristics: VDSS RDS(on) ID 75V 6.5mohm(typ.) 80A TO220 Marking and pin Assignment Schematic diagram Features and Benefits:      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 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 PD @TC = [ ... ]

SSF7509 PDF Datasheet Download