Invisible-in-Canal (IIC) hearing aids are the smallest invisible hearing aids available, and they are most suitable for people with mild-to-moderate hearing loss. Sitting deep inside the ear, the custom style is so small that there simply isn’t room for extra powerful speakers and stronger processing power. Completely-in-Canal (CIC) and In-the-Canal (ITC) invisible hearing aids are popular choices for those with mild-to-moderate hearing loss who want a little more control over their hearing aids.