Superlux HMD685, Intercom Headset, For IS103 Intercom System, Closed, Dynamic, With noise compensation, Colour: Black, Incl. 1.5 metre connection cable with 4-pin XLR female plug@+@+*Handset features:*@+@+, Frequency range: 20 - 20,000 Hz, Impedance: 200 Ohm, Sensitivity: 93 dB SPL @ 1 kHz, 1 mW max., 100 mW input power@+@+*Microphone characteristics:*@+@+, Dynamic, Polar pattern: cardioid, Frequency range: 50 - 15,000 Hz, Impedance: 250 Ohm, Sensitivity: -64 dBV/Pa (0.6 mV/Pa) @ 1 kHz