Diameter 25 cm / 10″ Power Handling (RMS) 250 Watts Impedance 4 Ohms Efficiency 87 dB Power Recommendation 200 – 300 Watts Voice Coil 50 mm / 2″ copper Membran HQPP cone with 3D-structure Max. Excursion (Xmax) 25 mm / 0.98″ Mounting Depth 129 mm / 5.08″ Resonance Frequency (Fs) 27 Hz Overall Qaulity (Qts) 0.44 Equiv. Air Volume (Vas) 49.3 L / 1.74 cu.ft..