A compressible hearing aid includes an exterior deformable skin which bounds an internal region which is filled, at least in part, with an open-cell foam, the foam can be wrapped around or molded to contain an audio output transducer. The skin is not self-supporting and in response to applied forces from user's ear canal, the skin and the foam both deform and readily compress exhibiting a reduced volume. Though compressed, the foam exerts an outward force against the skin thereby continuing to form an elongated seal between the skin and the external periphery of the user's dynamically changing ear canal. As the volume of the ear canal increases, the skin and open-cell foam expand, exhibiting an increased internal volume, while maintaining a comfortable seal with the ear canal. A plurality of external ribs carried on the skin not only reduces feedback but promotes drying of the ear canal and promotes retention of the hearing aid in the ear canal.