Features: This is a Best Sound Amplifier Adjustable Tone Hearing Aids Aid, Super mini size and light weight, not easily to be seen. 100% brand new sound amplifier behind the ear Super mini size and light weight, not easily to be seen Adjust volume to the minimum before wearing Choose an earplug of slightly bigger size to avoid whistler Increase volume gradually to avoid sudden increase in sound Max Saturated Sound Pressure: 125dB+4dB Sound gain: 50dB Harmonic Wave Distortion: 50% Frequency response Range: 300Hz~4000Hz Input Noise: 30 dB Power Voltage :1.5 V Current: 4mA Battery Type: AG13 button cell battery ( not included) Specifications: Original box: No Product Size: Approx. 92*70*27mm Net weight: 100g Package weight: 109g Color: Beige Packing content: 1 x Ear sound amplifier (batteries are not included) 3 x Earplug of different size