This part is a kind of semiconductor called 1N5618.

Function of this product has STANDARD RECOVERY GLASS RECTIFIERS.

Manufacturers : Microsemi

Image and pinout :

Some of the text within the PDF file :

SCOTTSDALE DIVISION 1N5614 thru 1N5622 VOIDLESS-HERMETICALLY-SEALED STANDARD RECOVERY GLASS RECTIFIERS WWW.Microsemi .COM DESCRIPTION APPEARANCE This “standard recovery” rectifier diode series is military qualified to MIL-PRF19500/427 and is ideal for high-reliability applications where a failure cannot be tolerated. These industry-recognized 1.0 Amp rated rectifiers for working peak reverse voltages from 200 to 1000 volts are hermetically sealed with voidlessglass construction using an internal “Category I” metallurgical bond. These devices are also available in surface mount MELF package configurations by adding a “US” suffix (see separate data sheet for 1N5614US thru 1N5622US). Microsemi also offers numerous other rectifier products to meet higher and lower current rati [ ... ]

1N5618 PDF Datasheet Download