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