Black Diamond Dia-12D4 Car Subwoofer 12" 500W Max Power, 250W, Dvc (1 Speaker). GREAT SOUND BUILT FOR TRUE AUDIOPHILES - Black Diamond DIA-12D4 12" Subwoofer puts out all of the power you need and handles low frequencies like a sub twice the price. POWERFUL BASS YOU CAN COUNT ON - Black Diamond DIA-12D4 delivers impressive 440W Max Power with 220W RMS at Dual 4 Ohm, once you hear it you'll finally realize what big, rich bass sounds like. DUAL VOICE COIL (DVC) - Provides multiple options and flexibility to wire Parallel, Series, or Independent. DVC will make sure you get the most from your system. While typical subwoofers have a single voice coil, Black Diamond offers two UNIQUE DESIGN - This ultra-reliable subwoofer has dual voice coils, paper dust cap, and foam edges all at an affordable price. What more can you ask for! HIGH-QUALITY MAGNET - Settle for nothing but the best with Ferrite magnets that produces a wider range of tones and can handle tremendous power at high volumes.