Powerbass XL84 8-Inch Single 4 Ohm Subwoofer Proprietary 4-layer, Non-pressed Paper, DDC Finish Cone Dynamic Damping Coating (DDC) Proprietary Composite Polycarbonate/Glass Fiber Basket - Dual 4-ohm Voice Coils 2 and 2.5" Vented BASV Voice Coil Formers - High Roll Santoprene Surround XTRA Large Motor Structures - Chrome Push Terminals Optimally Designed for Both Sealed or Ported Enclosures