EOps NOISEZERO iXi 2.0 Headphone Headsets for Smartphone Red SUPREME Magnet Drivers provides high sensitivity + wide dynamic range so that superior sudio can be generated from Smartphones 6.5mm Ultra-light PRECISION diaphragm improves sound response and redically reduces unwanted resonance of the diaphragm for better definition Frequency Response: 20 Hz  20 kHz Impedance: 16 Sound Pressure Level (SPL): 114dB (1kHz/1Vrms)