Effective Piston Area (Sd): 0.0444 sq m. Efficiency (1W/1M): 86.9786dB REVC: 3.5 Ohm BL: 15.4653TM VAS: 1.6456 cu ft. Nominal Impedance: 4 Ohm Power Handling: 1250 Max Earthquake’s next generation of TremorX subwoofers is ready to get louder and lower than any other subwoofer in its category. The new TremorX’s are built with TCT technology which allows the driver to play louder longer by keeping the voice coil running cool at all times. These bad boys also have stitched leads, reinforced dust cap construction for linear movement, and bigger, more effective magnets with added cooling devices to increase efficiency even more. The TremorX subwoofers have no equal and are ready to prove it. 12" 1250 Watt High Performance Subwoofer New design High SPL Stitched tensile leads Spring loaded terminals TCT (Turbine Cooled Technology) V-12 aluminum voice coil Thick high density magnet Pressed pulp fiber cone High roll surround