The behind-the-ear hearing aid is the most powerful but least attractive hearing aid. The in-the-ear hearing aid is the best choice for severe hearing loss. It is easy to adjust but is difficult to use with telephones. The in-the-canal hearing aid is used for mild to moderate hearing loss. This aid is relatively inconspicuous. The completely-in-the-canal hearing aid is used for mild to moderate hearing loss. This aid has good sound, is nearly invisible, and can be easily used with telephones. It is removed by pulling on a small string. However, it is the most expensive and hard to adjust.