- The PM400X4 marine grade full range delivers power and bass on demand - Perfect to drive a pair of coaxial speakers, component speakers, or a single subwoofer - Auto Turn-On circuit, On-board Punch EQ with +18dB boost @ 45Hz and 12dB/octave Butterworth crossover - 2.38 in x 7.76 in x 13.28 in - Full 2-year warranty