SB AUDIENCE NERO-15SW800, 404mm Paper Cone Pro Subwoofer 8 OHMFeatures Proprietary cone paper material with silk cotton tree and manila pulp Minimum damping fiber glass voice coil former 4.5" voice coil with APC (Advanced Polymer Coating) Cast aluminium chassis Vented pole piece for reduced compression Double spider for high stability suspension Cooling device on head yoke for increased heat transfer