Sony SAWX700 250 Watt Active Subwoofer (Discontinued by Manufacturer) Built-In Digital Amp with 250W into 3 ohms from 20 Hz-200 Hz, 0.8% THD Advanced SAW (Super Acoustically Loaded) Bass Reflex Design Dual 10" Drivers Frequency Response 20 - 200 Hz Line Output for Additional Subwoofer