IDMAX15 V.4 D2 - Image Dynamics 15" Dual 2-Ohm IDMAX V.4 Series Subwoofer 15" Dual 2 ohm ID MAX V.4 Series Subwoofer | Pressed paper composite cone woofer | Parabolic EPDM rubber surround | Over 2" long linear excursion | RaDiaToR cooling system for heat dissipation | Radiant Diametric Torsional Reinforcement High compliance suspension design | Flat spider with NOMEX cloth woven tinsel leads | High-temperature flat wire, flat wound voice coil | Inverted dust cap with logo | Powder coated alloy proprietary basket Power Handling: RMS: 1200 watts | Recommended Power Range: 300-1200 watts | Over 2" long linear excursion | 3-1/2" peak-to-peak surround excursion Nominal Impedance (IMP): Dual 2  | DC Resistance (Re): 1.4  | Resonance Frequency (Fs): 29.9 Hz | Equivalent Volume (Vas): 104.03 L | Electrical Q Factor (Qes): 0.65 | Mechanical Q Factor (Qms): 1.87 | Total Q Factor (Qts): 0.48 | Frequency response: 20-250 Hz Peak Excursion (Xmax): 44 mm | Force Factor (BL): 17.36 Tm | Piston Area (Sd): 934.79 cm2 | Sensitivity: 88.20 dB 1w/1m Sealed Enclosure Suggestion: 2 cu.ft. | Ported Enclosure Suggestion: 3 cu.ft. | Displacement: 0.26 cu.ft. | Mounting Depth: 10.40 in | Outside Diameter: 16.22 in | Cutout: 14.80 in