Product Description: Vibe OptiSound 8″ Woofer. 8″ woofer fits into the under-seat enclosure. Easiest plug play installation due to car-specific baskets and harnesses. System can be used as passive or semi-active system. Approved compatibility with Fitment 1-series (E81/E82/E87/E88), 3-series (E90/E91/E92/E93), 5-series (E60/E61/F10/F11), X1 (E84) ESOTERIC CONE: Composite cone using paper, and wood fibres for a lightweight and rigid cone producing a natural vocal reproduction NEODYMIUM MOTOR: All drivers feature powerful neodymium motors which deliver maximum magnetic force with shallow installation depth SHALLOW SUBWOOFER: Custom tooled 8 inch subwoofer directly replaces the under seat installed factory speakers delivering improved bass performance Package Includes.