4 Inch Ultrasonic Speaker Module with 40kHz Frequency Sound Laser Small Wireless Bluetooth Function Directional Speaker - AliExpress
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Pettersson L400 Ultrasound Speaker – Bat Conservation and Management, Inc.
ELTEM / PROPA-U100 / Directional Loudspeaker, Super Directional Speaker, Ultrasonic Speaker, Directional Sound System for Museums, Exhibits, Art Gallery and Digital Signage – Black : Amazon.ca: Everything Else
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DIY ultrasonic directional speaker
Parso Wireless Wearable Unidirectional Speaker Delivers Personal Sound | audioXpress