Superlux HMD685, Intercom Headset, For IS103 Intercom System, Closed, Dynamic, With noise compensation, Microphone mute function by flipping up the microphone, Colour: Black, 1.5 m long connection cable with 4-pin female XLR plug@+*Handset features:*, Frequency response: 20 Hz – 20,000 Hz, Impedance: 200 Ohm, Sensitivity: 93 dB SPL (1 kHz /1 Vrms), 100 mW input power@+*Microphone features:*, Dynamic, Polar pattern: Cardioid, Frequency response: 50 Hz – 15,000 Hz, Impedance: 250 Ohm, Sensitivity: -64 dBV/Pa (0.6 mV/Pa) @ 1 kHz