Amazon.com: DS18 Elite Z15 Subwoofer in Black - 15", 1,800W Max Power, 900W RMS, Dual 4 Ohms, DVC - Premium Car Audio Bass Speaker Great for Low Frequencies and High Power Applications (
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Amazon.com: DS18 EXL-X15.2D Car Subwoofer 15" 2500 Watts Max Power 1250 Watts RMS Fiber Glass Dust Cap Red Aluminum Frame Dual Voice Coil 2+2 Ohm Impedance - Competition Grade Bass - 1 Speaker : Electronics