https://www.global-be-star.com/
Electromagnetic Buzzer, Piezoelectric Buzzer, Speaker Module - BESTAR
BESTAR Holdings Co., Ltd. established in 2002, is a leading domestic provider of acoustic, sensing, and miniature active cooling components and solutions.
electromagnetic buzzerpiezoelectric speakermodulebestar
https://www.analog.com/jp/resources/design-notes/3v-supply-delivers-12vpp-to-piezoelectric-speaker.html
3V Supply Delivers 12VP-P to Piezoelectric Speaker | Analog Devices
specialized IC (stereo headphone driver) with internal charge-pump doubler is harnessed to the task of driving piezoelectric
piezoelectric speaker3vsupplydeliversanalog
https://newatlas.com/piezoelectric-waterproof-mobile-speaker/15438/
Introducing the world's first waterproof, ultra-thin piezoelectric speaker from Murata
May 2, 2015 - Murata has created the world's first waterproof, ultra-thin piezoelectric speaker for installation into mobile devices
world s first