A pair of Oticon Spirit Zest digital BTE (Behind the Ear) hearing aids.

In-the-ear aid

A modern behind the ear hearing aid, the audio tube to the speaker is barely visible.

A modern behind the ear hearing aid with a minicell battery.

A hearing aid is a small electrical machine which fits in or behind a person's ear. The purpose of a hearing aid is to make sounds louder so the deaf person can hear spoken words and other sounds.

The two most common types of modern hearing aids are behind the ear aids and in the ear aids.

Before hearing aids were invented, people used "ear trumpets" also called ear horns.