"Power tone V-168 In-Ear Hearing Aid is a quality hearing aid which can help you hear the sound clearly and loudly. The volume can be adjusted to 4 different levels. Features:Accurate and easy to use Volume can be adjusted with 4 levels. Help you hear the sound clearly and loudly, whether indoors or outdoors. Maximum loudness 130 5dB. Sensitivity: /= 50dB. Frequency range: 300Hz ~ 4000Hz. Total harmonic wave distortion :< /=5%Input noise :< /=30dBVoltage: 1.5VCurrent :< /= 4mA"