Pinnacle Speakers Digital Sub 200 12-Inch 200 Watt Front Firing Powered Subwoofer (Black) (Discontinued by Manufacturer) Anti-Clipping circuit for high level undistorted bass Includes high quality gold plated interconnect cable plus solid brass isolation cones for optimal bass resonse Line Level Input for fast hook up to your audio receiver Phase Switch to adjust for room acoustics and for high volume content Volume control