This compact subwoofer incorporates a number of Yamaha’s advanced and a high performance bass technologies such as Twisted Flare Port and Advanced YST II (Yamaha Active Servo Technology II) with discrete amp circuitry and high quality 20 cm (8”) woofer unit. This results in sensational bass response that enhances overall listening enjoyment of music and movies. New Twisted Flare Port contributes to clear and tight bass Advanced YST II (Yamaha Active Servo Technology II) 20 cm (8”) cone woofer Stylish addition to any room