MODEL: TRF SPL SW1230 D0.5 Size:12 inch Cone: competition grade paper Surround material: Foam Voice coil: 3.0inch Voice coile layer: 8layer Nominal impedance: dual 0.5ohm Voice coil wire:aluminium RMS Power: 3.000wrms MAX Watt:6.000wmax Sensitivity: 87.5dB Resonance frequency(f0): 40.9Hz Mechanical Q factor (Qms): 6.08 Mechanical Q factor(Qes): 0.55 Total Q factor:(Qts): 0.50 Xmax: 21mm Force factor: 22.9N/A Magnet Weight: 300Oz   1=Outer Dimension:  311mm - 12.2" 2=Mounting Depth: 228mm - 8.98" 3=Magnet Dimension: 226mm - 8.9" 4=Mounting Hole Dimension: 283mm - 11.1"