SSL SLR12D SLR Series 2500-Watt Dual 12-Inch 4-Ohm Voice Coil Subwoofer Subwoofers Component Subwoofers Frequency response 25Hz-2kHz Polypropylene Cone Aluminum Voice Coil, 2.5" Diameter Efficiency 1W/1M 96 dB Frequency response 25Hz-2kHz Mounting depth 6-9/16