This part is a kind of semiconductor called 1N4570.

Function of this product has 6.4V TEMPERATURE COMPENSATED ZENER DIODE.

Manufacturers : Digitron Semiconductors

Image and pinout :

Some of the text within the PDF file :

1N4565(A)-1N4584(A) High-reliability discrete products and engineering services since 1977 6.4V TEMPERATURE COMPENSATED ZENER DIODE FEATURES  Available as “HR” (high reliability) screened per MIL-PRF-19500, JANTX level. Add “HR” suffix to base part number.  Available as non-RoHS (Sn/Pb plating), standard, and as RoHS by adding “-PBF” suffix. MAXIMUM RATINGS Characteristics Operating and storage temperatures DC power dissipation Power derating Solder temperature IR = 2µA @ 25°C and VR = 3V Value -65 to +175°C 500mW @ 50°C 4mW/°C above 50°C 260°C for 10 s maximum ELECTRICAL CHARACTERISTICS Part number (Note 1) Zener test current (Note 3) IZT Maximum voltage temperature coefficient mA αvz ±%/°C ±mV/°C Temp. range 1N4565 .5 0.01 .64 0 to 75°C 1N4 [ ... ]

1N4570 PDF Datasheet Download