Dual 10 CompC Loaded Subwoofer Enclosure Signature Stitches - Kicker's signature yellow stitching creates a superior bond between the tough, ribbed polyurethane surround and polypropylene cone for the best in reliability. Poly Perfection - CompC subwoofers have a lightweight, injection-molded polypropylene cone to eliminate flex and distortion. You get a deep, accurate sound no matter how hard you push it. Stay Cool - Perimeter venting slots allow air to constantly circulate around the motor to maintain the perfect operating temperature.