The Bolero B is an audiologically identical hearing aid to the more popular Phonak Audeo B. The only difference between the two is the form factor. Bolero B is a BTE hearing aid that can be worn with an ear hook and traditional acrylic ear mold, or a slim tube. On the Bolero B, the microphone and speaker are both housed behind the ear in the hearing aid's casing, while with the Audeo B, only the microphone is behind the ear, with the speaker being in the ear canal. Some people prefer the form factor of the Bolero B due to the general reliability of BTE models vs RIC models like the Audeo B.