Sony Clip-on Stereo Headphones With Double Retractable Cord | MDR-Q68LW B Black (Japanese Imports) Review Posted on April 5, 2018June 25, 2018 by FancyPygmy Driver size is 30mm. Audio sensitivity : 108dB/mW Frequency Response Curve : 16-24,000Hz Impedance : 24Ω Maximum input : 1,000 mW (IEC)