Headphone: 1) Impedance: 32 ohms 2) Frequency response: 20-20kHz 3) Sensitivity: 108dB S. P. L. at 1kHz 4) 3.5mm stereo plug Microphone: 1) Frequency response: 20-20kHz 2) Sensitivity: -58dB +/- 3dB 3) Impedance: 2.2K ohms 4) 3.5mm stereo plug 5) Volume control optional