Hearing Aid Model lk138 Standard features: Middle output. Attractive design. Ultra-light weight. Less noise, fine fidelity and tone. With on/off switch. With imported microphone and receiver. Tested according to international standard iec118-7. Specification: Max sound output: 125f+5db Sound gain: fª43db Total harmonic wave distortion: f_8% Frequency range: 400----6200hz Input noise: f_28db Voltage: 1.5v Current: 10.8ma Battery: a675 zinc-air/ ag13 button cell
