value Sundown Audio PAIR of Rev3 (CLASSIC) SA-12 D4 12" at 750W RMS Subwoofer. The SA series was designed to be an excellent sounding sub woofer that is equally at home sealed or ported. We feel that the SA series is one of the best woofers available in it's price category and will satisfy the needs of a wide variety of users ranging from bass-heads to audiophiles!