SD-2 10D4 - Sundown Audio 10&quot; Dual 4-Ohm Subwoofer by Sundown Audio. $149.99. RMS Power Handling: 500 Watts Fs: 39.7 Hz Re: 8.0 ohms Qms: 5.45 Qes: 0.56 Qts: 0.52 Cms: 0.09 mm/N Mms: 178 g BL: 24.7 NA Vas: 13.8 L Sens: 83.5 dB 1w/1m Le: 4.06 mH Cut-Out Diameter: 9 1/4&quot; Mounting Depth: 4.75&quot; Outside Diameter: 10 1/2&quot;