Best Sound Amplifier Adjustable Tone Hearing Aids Aid Features: ? 100% brand new sound amplifier ? Super mini size and light weight, not easily to be seen ? Adjust volume to the minimum before wearing ? Increase volume gradually to avoid sudden increase in sound ? Powered by 2 x AG13 battery (included) ? Size: 3.0 x 1.6 cm (L X W) ? Color: as pictured Technical Specifications: ? Max Saturated Sound Pressure: 110dB+5dB ? Sound gain: ? 30db ? Harmonic Wave Distortion:? 10% ? Frequency response Range: 300--- 4000 Hz ? Input Noise: ? 40 dB ? Power Voltage :1.5 V ? Working Current : ?4mA ? Battery Type: AG13 button cell battery (included) Package included: ? 1 x hearing aid amplifier ? 3 x earplug (different size) ? 2 x AG13 button cell battery ? 1 x manual ? 1 x case