Arc Audio ARC-10D4 10” 4 Ohm Subwoofer Designed And Engineered In The USA High-Temperature Black Anodized Voice Coil Linear Design For Improved Dynamics And SPL At Low And High Volumes One Piece Molded Rubber Surround Stamped Steel Basket Progressive Flat Layered Spider With Integrated Tinsel Leads Designed For Small To Moderate Sized Sealed And Ported Enclosures Mounting Depth 5-1/2" Cutout Diameter 9-1/8" Minimum Sealed Enclosure - 0.65 cu ft Optimum Sealed Enclosure - 0.75 cu ft Maximum Sealed Enclosure - 0.90 cu ft Specifications - Power Handing (Peak) - 500 Watts Power Handling (RMS) - 250 Watts Impedance - Dual 4 Ohm Minimum Sealed Enclosure - 0.65 cu ft Optimum Sealed Enclosure - 0.75 cu ft Maximum Sealed Enclosure - 0.85 cu ft Cutout Diameter - 9-1/8" Mounting Depth - 5-1/2"