Skar Audio EV-10MB S4 10" Single 4-Ohm 400W Shallow Mount Loaded Subwoofer Enclosure 10-Inch Loaded Subwoofer Enclosure System Frequency Response : 30 Hz to 250 Hz Pre-Loaded EV-10 S4 - Single 4 Ohm 10" 400 Watt Subwoofer Sensitivity (1W/1m) : 85.2 dB Tight, accurate bass reproduction from a shallow and compact down firing enclosure design