Alpine S-W10D4 S-Series 10" Subwoofer with Dual 4-Ohm Voice coils. The new S-Series subwoofers use a new design that's almost 1-inch shallower than their predecessors, thereby making all the models good candidates for systems with limited space. The subwoofers also have an improved power rating of up to 600W RMS power handling. Features: High Amplitude Multi-Roll Surround High Strength Steel Frame Perimeter venting with airflow management system High-excursion underhung voice coil configuration Compound radius curve extended pole geometry Airflow optimized dual flare pole vent 65mm voice coil with high-temp 5-layer dvc winding on aluminum former high-grade strontium ferrite magnets 8-AWG push terminals with voice coil configuration jumpers Progressiver spider with reinforced tinsel leads Concealed mount gasket Reinforced parabolic cone structure with pulp/Kevlar con & PP/Mica/Talc Dustcap 15MM Xmax 64mm Xmech 600W RMS 4.7" mounting depth 10-9/16" Cutout Diameter Power handling: 250-600W RMS Sealed Enclosure range: .55-1.0 ft^3 Vented Enclosure Range: 1.0-1.5 ft^3 Vented tuning range: 32-37Hz