Yamaha 10" 100W Front-Firing Sub-woofer with Advanced YST II Linear Port For Minimizing Extraneous Noise, 10" Driver With Long-Stroke Cone, Black Finish Advanced YST II (Yamaha Active Servo Technology II) Front-Firing Active Subwoofer Linear Port for Minimizing Extraneous Noise 10 Long-Stroke Cone Driver with Magnetic Shielding High 100W Dynamic Power