AKG HC 644 MD, Condenser headset especially for fitness trainers, Slight frequency increase in the treble range for good speech intelligibility, Very light and low feedback, Elastic suspension for the suppression of background noise, Characteristic: Cardioid, Frequency range: 20 - 20000 Hz, Boundary sound pressure level: 135 dB, Impedance: 5 kOhm, Transmission factor: 20 mV / Pa, Colour: Black, Removable 3-pin TQG mini XLR connector fits AKG wireless systems, Suitable adapters for other systems available (not included)