Lmpedance(at 1KHz):150Ω+/-20%

SPL(318ear;60mV):95+/-2dB

Frequency:300-3400Hz

Axial Director(at  1kHz 0dB A/M):≥-19dB

Radial Director(at  1KHz 0dB A/M):≥-22dB

SD35 telephone receiver