CELESTION FTR123070C 12-Inch 350-Watt Subwoofer Power rating 1350W rms Nominal impedance 8 Sensitivity 296 dB Frequency range 40-4000 Hz Voice coil diameter 75mm/3 in Chassis typecast Aluminum Magnet type Ferrite Nominal diameter 305 mm/12 in Magnet weight 2.3kg/81 oz. Coil material Round copper Former material Glass Fibercon material Glass loaded paper with weather-resistant impregnation