Oumefar Mini 5pcs DC 3.3V-5V Alert Buzzer Module Electronic Active Sound Alarm Module for Electronic Toys Alarm Devices Timers

["Designed with holes for fixing with bolt , convenient to install .","External connection of 3 . 3V 5V voltage , can be directly connected to 5V micro controller and 3 . 3V micro controller .","Module is driven with 9012 transistor .","Convenient program control , single chip microcomputer high and low level can make it sound , better than a passive buzzer .","This active buzzer has internal oscillation source , so it will alarm as long as being energized ."]