A free program for Android, by GN Hearing.

Enhance Pro is an Android-based hearing aid app that can work with the following types of hearing aids:

The device has a built-in microphone and a built-in speaker. It can also be used as a wireless microphone or as a Bluetooth microphone. It supports a variety of audio formats, including MP3, OGG, WAV, FLAC, and others. It supports both automatic and manual sound adjustment. It can be used as a hearing aid for people with mild hearing loss, as a listening device for people who are deaf or have hearing loss, and as a personal sound amplifier. It has a built-in sound-enhancing algorithm. It can be used with Bluetooth or Wi-Fi. It can be used with or without an external Bluetooth controller.