Polyurethane surround ^^ PEI dome tweeter ^^ Multi-direction pivot tweeter system ^^ Durable and High-Quality Build Features a black-on-black polypropylene cone, stitched butyl rubber surround, and reinforced spider for maximum strength and long-term reliability. ^^ Compact Yet High-Performance Design A five point one inch mounting depth, sixty-three ounce magnet, and two inch high-temperature voice coil make this subwoofer a perfect fit for powerful custom installations.