Sennheiser CX200 Twist-to-Fit Earbuds Black&Gray Innovative holding system (Twist-to-Fit system) ensures best possible fit, High passive attenuation of ambient noise. Impedance: 16 , Frequency Response: 20 - 20000 Hz, Sound Pressure Level (SPL): 110 dB, THD (total harmonic distortion): &lt;0.2%, Cable Length: 1.2 m, Transducer Principle: Dynamic, Weight Approx: 5 g Powerful, bass driven stereo sound Optimized for MP3, iPod, iPhone, CD players and portable gaming systems Symmetrical Cable