Yamaha's Advanced YST II technology, the Frontfire principle and the Linear Port provide the YST-SW012 with incredibly powerful sound, depth and clarity. Thanks to the bass reflex opening placed on the side, the subwoofer ensures optimal sound distribution. The classic design can be integrated into all living areas without any problems. Optically and technically in good condition. Advanced YST II (Yamaha Active Servo Technology II) Front firing active subwoofer Linear Port for minimizing extraneous noise 20cm (8”) cone driver with magnetic shielding High 100W dynamic power 28–200Hz low frequency response Single scrach on the top as showned on the pictures.