This app transforms your phone into a pair of hearing aids, one for each ear. You will need to use a headset. The app amplifies ambient sounds like a typical hearing aid, plays and amplifies musics stored in your phone.
The app can also test your hearing and automatically calculate the amplification for your hearing level.
You can further adjust the amplification. Your adjustments can be saved as a program. You may save as many programs as you want. You can load a saved program using at any time.
In order to get the best out of the app, it is recommended to use AirPod Pro or a pair of wired headphones or earphones. If you need a lot of amplification, headphones/earphones with active noise cancellation would afford you a best listening experience.
If you use a bluetooth headset, you can use your phone as a remote mic and place it near the person you want to hear clearly.