Transfer your smartphone into a handy Hearing Aid device. Just select the audio source (microphone, internal file or file on the web), plug in your Bluetooth device (or any type of earphones) and listen. Use the Boost button to boost the audio in your neighborhood. You may also use the application to listen to music or lectures when the audio signal is not strong enough. Excellent for elderly people who are expiring hearing loss, or students listening to a lecture in the university, or people who are having difficulties in hearing the TV audio signal. Audio can come from a variety of sources (Microphone, Internal File or a file on the web). You select the source, plug in your earphone (Bluetooth or others) and listen. Very simple to operate. No instructions needed. Privacy Policy: https://sites.google.com/view/axelaudiobooster/ Terms of Use: https://sites.google.com/view/axelaudiobooster-termsofuse/