Zenith "Diplomat 5" Behind-the-Ear Hearing Aid The Zenith "Diplomat 5" was a four transistor BTE aid manufactured in 1959. It was considerably smaller than its 1956 predecessor and measured just 2¼" by 5/8". Like the previous model, it also had an external receiver and used a 675 battery. |  | Click picture for larger view | | | | |