Inside the sub, the poly-cotton, semi-progressive-roll spider supplies substantial stability for the loudest bass possible. Externally, a ribbed Santoprene surround protects the cone during max excursion. The CompVX 10-Inch Subwoofer works best with a sealed or ported enclosure and 600 watts of recommended power. Features: Kicker 44CVX104 Comp VX CVX 10" 1200 Watt Car Subwoofer Sub CVX10-4 44CVX10-4 Dual Four-Ohm Voice Coils Thick Polypropylene Cone Signature Double Blue Surround Stitching Ribbed Santoprene Surround SoloKon Cone Reinforcement Oversized Suspension System High-Strength Insulated Tinsel Leads High Temp Voice Coil Perimeter Venting for Thermal Management Massive Ceramic Magnet UniPlate Extended Pole Piece and Backplate For Superior Heat Dissipation Cast Aluminum Basket Satin Nickel Spring-Loaded Speaker Terminals Size: 10" (25 cm) Impedance: 4 Ohms DVC Power Handling: 1200 Watts Peak / 600 Watts RMS Sensitivity: 85.7 dB 1w/1m Frequency Response: 24 Hz - 500 Hz Mounting Depth: 5-15/16" (15.1 cm) Mounting Cutout: 9-3/16" (23.3 cm) Min Sealed Box Vol: 0.8,cu. ft (22.7 L) Max Sealed Box Vol: 3.0 cu. ft (85.0 L) Min Vented Box Vol: 1.25 cu. ft (35.4 L) Max Vented Box Vol: 1.75 cu. ft (49.6 L) What's in the box: one 10-inch subwoofer, one owner's manual, two stickers