LD Systems ICOA SUB 18A 2,400W Powered 18" Subwoofer600W RMS 2,400W peak Class D power amp boasts a 133dB maximum SPL 18 inch woofer and optimized bass reflex ports yield low end all the way down to 29Hz Proprietary DynX DSP give you distortion free sound at maximum volume 4 intuitive sound presets ensure perfect balance with the rest of your system Switchable signal polarity Delay line function compensates for distances up to 33 feet Excursion limiter, over voltage, over current, peak limiter, and