The Sennheiser IE 300 is a premium, wired in-ear monitor (IEM) designed for audiophiles who want high-fidelity sound in a highly portable format. Transducer Type: Single 7mm TrueResponse dynamic driverFrequency Response: 6 Hz – 20,000 HzImpedance: 16 ohms (highly efficient and easy to drive off mobile devices)Total Harmonic Distortion (THD): < 0.08%Cable Connection: Detachable Fidelity+ MMCX connectors with a 3.5mm plugPassive Noise Isolation: Up to -26 dB of ambient attenuation