This part is a kind of semiconductor called 1N749A.

Function of this product has SILICON 500 mW ZENER DIODES.

Manufacturers : Microsemi Corporation

Image and pinout :

Some of the text within the PDF file :

1N746 thru 1N759A, -1 and 1N4370 thru 1N4372A, -1 DO-35 Silicon 500 mW Zener Diodes SCOTTSDALE DIVISION DESCRIPTION The popular 1N746 thru 1N759A and 1N4370 thru 1N4372A series of 0.5 watt Zener Voltage Regulators provides a selection from 2.4 to 12 volts in standard 5% or 10% tolerances as well as tighter tolerances identified by different suffix letters on the part number. These glass axial-leaded DO-35 Zeners are also available with an internal-metallurgical-bond option by adding a “-1” suffix. These are also available in JAN, JANTX, and JANTXV military qualifications. Microsemi also offers numerous other Zener products to meet higher and lower power applications. IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com APPEARANCE WWW . Micros [ ... ]

1N749A PDF Datasheet Download