Nominal Diameter: 320/12 mm/inch Rated Impedance: 8 ohm Max Power: 500 watts RMS Power: 250 watts Sensitivity: 98 dB Frequency Range: 50-4000 Hz Effective Piston Diameter: 282/11.1 mm/inch Minimum Impedance: 6.7 ohm Voice Coil Diameter: 65.5/2.5 mm/inch Voice Coil Material: Aluminium Voice Coil Winding Depth: / Number of layers: 2 Kind of layer: outside Top Plate Thickness: 12/0.47mm/inch Cone Material: no pressed pul Cone Design: curved Surround Material: polycotton Surround Design: m-roll