Alpine R-SB10V Halo Series 10" Linkable Ported Subwoofer EnclosureAlpine's subwoofer enclosures make it easier to add more bass to your system. You'll get the low end you're looking for from one box, but when you want to expand your system, you can add a second enclosure and the optional linking kit to create a single two speaker system with double the impact. Dishing it out The R SB10V comes loaded with Alpine's R W10D4 subwoofer wired for 2 ohm impedance. The sub's Kevlar reinforced cone and Santoprene surround