What image comes to mind when someone says "hearing devices?"
Most individuals think of a single listening instrument, or purpose they are used for but the term is non-specific and can refer to a variety of tools.
In fact, listening instruments are used to aid those who suffer from hearing loss, musicians and even hunters.
A large majority of listening instruments are used by the hearing impaired. Here, we're talking about BTE, ITE, CIC and other hearing aids.
People rely on them to live, work and play comfortably and with adequate sound.
There is another class of listening devices used to augment sound. These may be used by law enforcement, game hunters and others looking to gain a critical advantage a heightened sense of sound can deliver.
Consider a hunter pursuing game that is cloaked by forest, laying in wait somewhere in the distance. Listening instruments that improve hearing by 7 times gives this hunter a "super" human advantage.
Consider musicians, who's livelihood and practice depends as much on good hearing as it does playing an instrument or singing. In this case, a good listening instrument allows band members to get the best music mix possible.
Finally, there have to be those tools that are used by hobbyists and professional eavesdroppers, wearing a set of earphones and holding a directional microphone designed to pick up sounds in the distance.