Yamaha YST-SW225 Advanced YST II and QD-Bass Subwoofer, Black (Discontinued by Manufacturer) Magnetically shielded 120-watt powered subwoofer with black wood-finished cabinet QD-Bass and Advanced YST II technologies efficiently spread bass response throughout room 8-inch multi-range driver; highly efficient internal amplifier; linear port minimizes noise Bass Action Selector System optimizes sound for movies and music 28 to 200 Hz frequency response; 11.44 by 13.88 by 13.75 inches (W x H x D)