This part is a kind of semiconductor called STK3041.

Function of this product has (STK30xx) Voltage Amp for 30 to 100W AF Power Amp.

Manufacturers : ETC

Image and pinout :

Some of the text within the PDF file :

w w a D . w S a t e e h U 4 t m o .c w w w .D t a S a e h t e U 4 .c m o w w w .D a S a t e e h U 4 t m o .c [ ... ]

STK3041 PDF Datasheet Download