You want a powerful, audiophile bass reproduction, but do not want to see the subwoofer? Then the ISW-4 in-wall subwoofer is the ideal speaker for you. Thanks to its two 200mm long-throw drivers, it can easily move the large volumes of air that are essential for outstanding low-frequency reproduction. The ISW-4 is mounted in its own ultra-stable in-wall box and powered by a separate audiophile-grade 250 W Class D amplifier, the SA250 (available as an option)