... Kownless of USA, earphone are inside the body,K-618 Behind the ear Hearing Aid1. power increasing range2.stability of output ... electrocircuit can leach outside noise and protect eardrum. K-618 behind the ear hearing aid (inside earphone) Max Sound Output: 129 ... Current: ≤3 mA Net Weight: 8.5 g (without Battery) Behind the ear hearing aid K-618