JBL Sub 550P High-Performance 10" Powered Subwoofer Sealed Enclosure with Built-in 300-Watt RMS Amplifier 10-Inch cellulose-fiber cone is both strong and light Powerful 300-watt amplifier A JBL computer-optimized bass-reflex port provides deeper bass and less turbulence Use of premium components gives you less distortion Adjustable crossover frequency optimizes subwoofer performance Use of premium components gives you less distortion These speakers are designed to look good anywhere with a style that equals their substance The JBL ES Series uses cellulose-fiber cones reinforced with a ploymer coating for uniform pistonic motion Matches other speakers in the JBL ES line