Noise-Free Function Behind The Ear Rechargeable Hearing Aid Specification: Max Sound Output(SSPL): 128 ± 3dB Sound Gain(SSPL): ≥50dB Input Noise: ≤26dB Frequency Range: 400-4200Hz Working Current: 3.5mA Total Harmonic Wave Distortion: 500Hz <= 3% 800Hz <= 5% 1600Hz <= 1% Rechargeable Battery: NI-MH Recharge Time: 7 hours Working Time: 16 hours Dimension: 40mm x 13mm x 10mm Operationg Temperature: 0℃ - 40℃ Storage Temperature: -10℃ -...