Alpine MRP-M500 car amp.
Mono subwoofer car amplifier
200$
Specfications:
300 watts RMS x 1 at 4 ohms (500 watts RMS x 1 at 2 ohms)
variable low-pass filter (50-200 Hz, 24 dB/octave)
variable bass boost (0-12 dB at 50 Hz)
subsonic filter (15 Hz, 24 dB/octave)
Class D amp with MOSFET power supply