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Amazon.com: VOYZ 400 Watts Max Power Speaker Tweeter - 3.5” Piezo Super Horn Tweeters with Aluminum Diaphragm and High Temperature Voice Coil - 4-8 ohms for Speaker Box or Sound Project 1 Pair (2pcs) (PET-1918) : Electronics
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