MODEL:TRF SW1530D0.5 Size:15 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: 88.7dB Resonance frequency(f0): 37.7Hz Mechanical Q factor (Qms): 6.11 Electrical Q factor(Qes): 0.61 Total Q factor:(Qts): 0.55 Xmax: 21mm Force factor: 15.1N/A Magnet Weight: 300Oz   1=Outer Dimension:  392mm - 15.4" 2=Mounting Depth: 268mm - 10.6" 3=Magnet Dimension: 226mm - 8.9" 4=Mounting Hole Dimension: 363mm - 14.3"