Sleepyheads by PrivateMe

The app, Sleepyheads, in your Firefox browser. Perfect for a good nights sleep!

The best sounds for a good sleep
Sleepyheads has a wide range of sounds on offer

Use in Firefox
No massive downloads, just click 'Add to Firefox' and you're ready for the best sleep!

Notes
There is a dark mode button which won't work in Firefox. This is because in the extension's code JavaScript is disabled. You can't do anythink about it, it's in the code of the add on.