Boss S10A 10" 800W 4-Ohm Amplified Subwoofer Enclosure THE ENCLOSURES ARE CUSTOM DESIGNED AND TUNED TO THE SUBWOOFERS THEY HOUSE. THE BUILT-IN AMPLIFIER IS A PERFECT MATCH DRIVING THE SUBWOOFERS TO THEIR MAXIMUM WITHOUT DISTORTION AND WITH PLENTY OF HEADROOM. Built-in MOSFET power amplifier; 10-inch subwoofer Frequency response: 40-200Hz; Impedance: 4 ohms; Sensitivity: 92dB RMS power: 400 watts; Max power: 800 watts