Self contained miniature SMD mounting tone alert has built in electronic driver to cause a penetrating tone to be produced when 1.5V up to 12VDC is applied. No driver or other electronic parts needed. Size only 0.67" square x 0.29" tall. Has 2 metal tabs for surface mount connections or you can just solder leads to the tabs. Retails for about $5.00 each.
Sold in a package of 10.