This part is a kind of semiconductor called 1N4748A.

Function of this product has 500mW ZENER DIODES.

Manufacturers : SENSITRON

Image and pinout :

Some of the text within the PDF file :

ZENER DIODES SENSITRON SEMICONDUCTOR OPERATING AND STORAGE TEMPERATURE –55°C TO+200°C 500mW ZENER DIODES / DO-35/DL-35 (MINI MELF) TYPE Nominal Zener Voltage VZ @IZT Min BZX / BZV 55 C 2V4 BZX / BZV 55 C 2V7 BZX / BZV 55 C 3V0 BZX / BZV 55 C 3V3 BZX / BZV 55 C 3V6 BZX / BZV 55 C 3V9 BZX / BZV 55 C 4V3 BZX / BZV 55 C 4V7 BZX / BZV 55 C 5V1 BZX / BZV 55 C 5V6 BZX / BZV 55 C 6V2 BZX / BZV 55 C 6V8 BZX / BZV 55 C 7V5 BZX / BZV 55 C 8V2 BZX / BZV 55 C 9V1 BZX / BZV 55 C 10 BZX / BZV 55 C 11 BZX / BZV 55 C 12 BZX / BZV 55 C 13 BZX / BZV 55 C 15 BZX / BZV 55 C 16 BZX / BZV 55 C 18 BZX / BZV 55 C 20 BZX / BZV 55 C 22 BZX / BZV 55 C 24 BZX / BZV 55 C 27 BZX / BZV 55 C 30 BZX / BZV 55 C 33 BZX / BZV 55 C 36 BZX / BZV 55 C 39 BZX / BZV 55 C 43 BZX / BZV 55 C 47 BZX / BZV 55 C 51 BZX / BZV 55 C [ ... ]

1N4748A PDF Datasheet Download