Sundown Audio X-8 V.2 D4 8" Dual 4-Ohm X-V.2 Series Subwoofers Xmax = 19mm one-way by 70% BL | RMS Power = 750-watts | Solid Pole piece with chamfered edges & machined air channels for increased voice coil cooling High velocity under-spider frame vents | Black Aluminum 2.5 voice coil former for superior heat dissipation | High Temperature copper voice coil wire Large aluminum faraday ring (Magnet ID) | Spring Loaded Terminals | Stitched-On Double High-Power Tinsel Lead Wires High strength & patented cast aluminum frame | Optimized for small ported enclosures | Ported Enclosure Size Recommendations: .75-1.0 ft^3 | Mounting Depth: 7.00" | Outside Diameter: 8.70" | Cut-Out: 7.36" | Recommended Tuning: 32hz | Recommended Port Area: 12-16 in^2