Monoprice Monolith 13in THX Ultra Certified 2000 Watt Powered Subwoofer Massive Output, Low Distortion, For Studio and Home Theater Systems Audio / Video Accessories - Newegg.com
Amazon.com: Monolith 13 Inches THX Ultra Certified 2000 Watt Powered Subwoofer Massive Output, Low Distortion, for Studio and Home Theater Systems : Electronics
Amazon.com: Monolith Powered Subwoofer - 15 Inch with 1,000 Watt Amplifier, THX Certified, Ideal for Professional Studio and Home Theater : Electronics