This part is a kind of semiconductor called AZ12.

Function of this product has Tube.

Manufacturers : TELEFUNKEN

Image and pinout :

Some of the text within the PDF file :

page 1 2 3 AZ12 sheet 010342-a 010342-b FP date 1942 1942 2000.03.04 [ ... ]

AZ12 PDF Datasheet Download