DESC: Alpine Type-R subwoofers are designed with HAMR Engineering to deliver tighter, accurate bass. A multi-stage Thermal Management System and Aluminum Airflow Motor Cover provide better airflow cooling for maximum performance, With the precision-crafted SWR-1242D (12, 4ohm + 4ohm), you'll be able to handle ground-pounding, long-lasting bass and complement any system for awesome sound quality. Add another dimension to the sound, and feel your music!