Alpine SWR-1542D 15" 2000 Watts Dual 4 Ohm Voice Coil Car Sub SubwooferAlpine SWR 1542D 15" 2000 Watts Dual 4 Ohm Voice Coil Car Sub Subwoofer Built from select materials and high end components, designed for precision and efficiency, and protected by Thermal Management features the Type R subwoofers provide the kind of real power and massive bass only hinted at by other speakers. HAMR Engineered Airflow Cooling System This meticulously designed system uses various techniques and technologies, many patent pending, to