JBL MPS1000 10-Inch 250-Watt Powered Marine Subwoofer 10-inch, 250-watt powered marine subwoofer engineered for harsh marine conditions Integrated amplifier and enclosure; mounts like a car subwoofer Built-in 12dB electronic crossover allows adjustment between 70Hz and 170Hz Built-in bass EQ provides 40Hz adjustment between -6dB and +3dB Controls are located on the front panel under a watertight protective cover; one year warranty