Skar Audio EV-12MB S2 12" Single 2&Omega; 500W Shallow Mount Loaded Subwoofer Enclosure 12-Inch Loaded Subwoofer Enclosure System Frequency Response : 20 Hz to 250 Hz Pre-Loaded EV-12 S2 - Single 2 Ohm 12" 500 Watt Subwoofer Sensitivity (1W/1m) : 87.6 dB Tight, accurate bass reproduction from a shallow and compact down firing enclosure design