SB AUDIENCE ROSSO-18SW1000D, 483mm Paper Cone Pro Subwoofer 8 OHMFeatures Proprietary cone paper material with silk cotton tree Double spider for high stability suspension Shorting ring in motor system for reduced distortion Cooling device on yoke for improved heat transfer 4.5" voice coil with APC (Advanced Polymer Coating) AISVW voice coil wire for high power handling Cast aluminium chassis