A subwoofer enclosure that sounds as good as it looks. Alpine’s preloaded (S2-SW12D4), linkable subwoofer enclosures give you powerful performance with the unique Alpine Halo design. ProLink is unique to Alpine and allows you to connect two S2-SB12V sub enclosures together using the KTX-H12 linking kit (sold separately), for a compact, sturdy dual-subwoofer solution. | Alpine | | Halo S-Series Single 12" Dual Voice Coil 2-Ohm Preloaded Subwoofer Enclosure with ProLink | Black | Best Buy