IIC hearing aids are custom-made for every patient, by initially taking a deep impression of the ear canal up to the second bend. They are practically invisible (and hence the name, Invisible In the Canal) as they fit deeper into the ear canal than CIC hearing aids. They use smaller batteries, and therefore, have a shorter battery life. Although they are susceptible to occlusion (a feeling of blocked or plugged-up ear) and feedback, they are suitable for addressing mild to moderate hearing loss while also not making the wearer feel conscious about their visibility to others.