Ooooo is a straightforward iPhone app designed to help you achieve a chosen mind-state by generating binaural beat audio waves through your headphones. Developed by Pavlos Tsochantaris, this app is perfect for those seeking relaxation, meditation, improved sleep, or a quick energy boost.

Unlike other similar apps that are overloaded with features and come at a cost, Ooooo is completely free and works offline. It also does not contain any ads or invasive tracking. Additionally, there is an Apple Watch app included, allowing you to use the app even when you are away from your phone.

The app's main function is to generate the desired binaural frequency audio hum, along with optional white or brown noise to mask external sounds. You can easily combine the app's audio with other sound generators or play your favorite music or radio in the background. Ooooo focuses solely on creating the brainwave frequency you need and leaves the rest up to you.