Model:High-Quality Flat SPL Subwoofer Diameter:20 cm / 8″ Power handling (RMS/SPL):500 / 800 Watts Impedance:2x 2 Ohms Efficiency:83 dB Power recommendation:350 – 800 Watts Voice coil:63 mm / 2.5″ Copper Cone:Sandwich paper Max. Excursion (Xmax):24 mm / 0.94″ Mounting Ø:187 mm / 7.36″ Mounting depth:80 mm / 3.15″ Resonance frequency (Fs):31.5 Hz Overall quality (Qts):0.41 Equiv. air volume (Vas):14.2 L / 0.50 ft³