Polk Audio PSW10 10" Monitor Series Powered Subwoofer from Amazon

Single 10-inch subwoofer in black with built-in high-current amplifier for big bass Equipped with one 10-inch polymer-composite dynamic-balance cone driver Laser-based Klippel measurement technology for improved linearity and deep, precise sound Non-resonant all-MDF enclosure construction with 0.75-inch-thick baffles and internal bracing Measures 14 by 14.38 by 16.12 inches (WxHxD)