Description:Brand new and high quality hearing aid sound amplifierSuper mini size and light weight， not easily to be seenAdjust volume to the minimum before wearingIncrease volume gradually to avoid sudden increase in soundConvenient for watching movie， enjoying the drama， attending meeting， or having class， it could help you hear the sound clearly and loudly.Max sound output: 110??5dBSound gain: ?��30dBTotal harmonic wave distortion: ??10%Frequency range: 300-4000HzInput noise: ??40dBVoltage: DC1.5VCurrent: ??4mABattery: AG3 button cellsize: 19?��14?��16 mm Notice: Battery no included Package Included:1 x Hearing Aids4 x Units of earplug of different size1 x Case1 x Operation Manual