JBL believes sound quality should never be compromised and the Stadium subwoofers make sure you don't have to compromise flexibility, either. That's because these high-performance subwoofers feature SSI (Selectable Smart Impedance), an exclusive impedance switch that lets you select the optimum impedance—2 or 4 ohms—providing multiple system configurations and flexibility. A special aero-cooling design keeps the voice coil cool even at high output levels. This feature coupled with oversized voice coils increases power handling and ensures long term reliability. More power, more reliability, more flexibility—and no compromises. When you're ready to step up, Stadium is your subwoofer. What's In The Box 1 Subwoofer 1 User Manual 1 Bag Of Screws Technical Specifications: 12" (300mm) high-performance car audio subwoofer Power Handling: 500W RMS, 1500W peak Sensitivity (@ 2.83V): 92dB Frequency Response: 25Hz – 175Hz Voice Coil Diameter: 2 in. (50mm) Impedance: 2 or 4 ohms Cutout Diameter: 11-1/5" (285mm) Mounting Depth: 7" (180mm)