Alpine Subwoofer Package Two S W12D4 S Series 12" Dual 4 Ohm Subwoofers Wolf Grey Cool Grey White Pink Foam The closed cell urethane foam jounce The closed cell urethane foam jounce bumper inside the ULTIMATE air springs provide a cushion of air that absorbs shock Publisher: Glove It 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 5 1 16" mounting depth 10 9 16" Cutout Diameter Power handling: 250 600W RMS Sealed Enclosure range: 5 ft^3 Vented tuning range: 32 37Hz