It plays carefully tuned low frequencies that vibrate the speaker membrane and push trapped water out - the same approach the Apple Watch uses, with presets for the earpiece and the bottom speaker.
The frequencies are chosen to stay within safe limits for the driver, and there is a cycle timer rather than an indefinite tone.
Those have their own considerations - see water in AirPods and Apple Watch. This app plays through the device it runs on.
iPhone, iPad, Mac and Vision Pro.
You’re browsing inside Instagram, and its built-in browser isn’t allowed to hand links over to the App Store. Open this page in Safari and the link will work.
Tap the three-dot menu at the top right, then choose Open in external browser.