Pair of SA-8 V1.5 D4 - Sundown Audio 8" Dual 4-Ohm SA V1.5 Series Subwoofer RE: 3.28 ohms (series) | FS: 41.6 Hz Sens: 78.476 dB @ 1w/1m | Power: 400 RMS Depth: 5.25" Overall basket OD (no gasket): 8.25" | Cut-out diameter (without gasket): 7.375" | Cut-out diameter (with gasket): 7.25" | Magnet diameter: 6.25" XMAX: 16.5mm one way