This part is a kind of semiconductor called 1N975B.

Function of this product has 500mW SILICON ZENER DIODES.

Manufacturers : Digitron Semiconductors

Image and pinout :

Some of the text within the PDF file :

1N957B-1N992B High-reliability discrete products and engineering services since 1977 500 mW SILICON ZENER DIODES 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 Rating Operating temperature Storage temperature Thermal resistance Steady-state power Forward voltage Solder temperature Value -65°C to +175°C -65°C to +175°C 250°C/W junction to lead at 3/8” lead length from body, or 310°C/W junction to ambient when mounted on FR4 PC board(1) 0.5W at TL ≤ 50°C 3/8” from body or 0.48W at TA ≤ 25°C when mounted on FR4 PC board (1) @ 200 mA: 1.1 volts maximum (1N957B-1N985B) @ 200mA: [ ... ]

1N975B PDF Datasheet Download