The Completely-In-Canal (CIC) style hearing aid is the smallest style of hearing aids. It goes completely into the ear canal. When the CIC was first developed, it could only be used with individuals with mild to moderte hearing loss. But with the advancements in digital technology, this style can even help individuals with severe hearing loss. The major draw back is the very small battery which must be changed more often.
Hearing Aid Styles - CIC