This part is a kind of semiconductor called ABT-402-RC.

Function of this product has Piezo Buzzer.

Manufacturers : pro-SIGNAL

Image and pinout :

Some of the text within the PDF file :

PART NO. ABT-402-RC ECN # REV -A REVISIONS DESCRIPTION RELEASED DRAWN DATE CHECKD DATE APPRVD DATE ASH 8/12/11 JAG 8/12/11 22/12/11 Tolerance: ±0.5 Dimensions : Millimetres Important Notice: This data sheet and its contents (the "Information") belong to the Premier Farnell Group (the "Group") or are licensed to it. No licence is granted for the use of it other than for information purposes in connection with the products to which it relates. No licence of any intellectual property rights is granted. The Information is subject to change without notice and replaces all data sheets previously supplied. The Information supplied is believed to be accurate but the Group assumes no responsibility for its accuracy or completeness, any error in or omission from it or for any use made of i [ ... ]

ABT-402-RC PDF Datasheet Download