Specially engineered for ergonomic comfort and durability. Behind the neck headband design provides added stability during activity. Reproduces harmonic and superbly transparent sound. Tangle-free single entry cord. Uses 3.5mm Stereo plug and includes 6.3mm phono size plug adapter. Driver units 34 mm cobalt magnet Impedance 32ohms +/-10% Frequency response 20hZ-20kHz Sensitivity 111dB +/- 3dB @ 1kHz Max power 100mW