The EVID 12.1 is an attractive and powerful subwoofer designed to augment and extend the low-frequency response of any full-range model. The 12.1 allows easy installation by incorporating dual-voice coils to manage both channels of a stereo pair. In addition, the unit can power up to four satellites with its four crossed-over audio outputs on the back panel. Use the EVID 12.1 subwoofer for extended bass performance in demanding installations.