Infinity's Kappa 1200W 12" Subwoofer features the exclusive Selectable Smart Impedance design, allowing you to build exactly the system you want, high-power or multi-sub, without complicated wiring. Just flip the convenient impedance switch to safely choose between 2 or 4 ohms If you're thinking of upgrading your amp or adding another subwoofer later, this subwoofer is easy to reconfigure and almost impossible to miswire..PZA MORE SPECS