Model High power midwoofer Diameter 165 mm / 6.50″ Power Handling (RMS/max.) 120 / 180 Watts Impedance 4 Ohms Efficiency 87 dB Frequency Response 40 Hz – 5000 Hz Voice Coil 38 mm / 1.5″ CCA Membran Layout Scooped paper Mounting Ø 144 mm / 5.67″ Mounting Depth 69 mm / 0.27″ Resonance Frequency (Fs) 49.4 Hz.