Buzzer, 3-24 V piezoelectric Electronic Audible Summer Alarm, Continuous Tone, Cable Length 100 mm, Door Buzzer: Amazon.com: Industrial & Scientific
Amazon.com : 6 Pcs Active Piezo Electric Buzzer Alarm, DC 3-24V Low Voltage Buzzer Beep Tone Speaker Alarm with Lead Wire for Classroom, Game Show, Physics Circuits Intermittent Sound : Electronics
Amazon.com: E-outstanding 2pcs Piezo Electronic Buzzer Beep Tone Alarm Ringer Continous Sound 3-24V Buzzer Electromagnetic for Arduino DIY Buzzer, Black : Electronics