Sundown Audio Z-12 V.5 D2 12" 2000W RMS Dual 2-Ohm Z-V.5 Series Subwoofer Dual 2-Ohm 2000W RMS Z-V.5 Series Subwoofer Specifications: DC Resistance (Re): 4.0  | Resonance Frequency (Fs): 35.6 Hz | Equivalent Volume (Vas): 17.6 L | Electrical Q Factor (Qes): 0.53 | Mechanical Q Factor (Qms): 4.33 | Total Q Factor (Qts): 0.47 | Voice Coil Inductance (Le): 1.78 mH | Force Factor (BL): 22.5 NA | Moving Mass (incl. Air Load) (Mms): 298.7 g | Suspension Compliance (Cms): 0.07 mm/N | Sensitivity: 83.6 dB 1w / 1m Box Recommendations: Sealed Enclosure Suggestion: Not Recommended | Ported Enclosure Suggestion: 25 cu. ft. | Displacement: 0.23 cu. ft. | Depth: 11.27 in | Outside Diameter: 12.67 in | Cutout: 11.09 in | Recommended Tuning: 32 Hz | Recommended Port Area: 40 sq. in.