Kicker 43DXA250.1 250-Watt Monoblock Class D Subwoofer Car Amplifier Switchable high and low level input works with any system Line output for multiple amp options 12 dB variable bass boost, enhances the deep bass you&apos;re listening for Subsonic filter 25 Hz, 24 dB/octave for cleaner bass Variable input gain control balances the sound with the rest of your system