JL AUDIO JD250/1D Mono Subwoofer Car Audio Amplifier. Monoblock Class D Subwoofer Amplifier, 250 W x 1 @ 2 Ω / 160 W x 1 @ 4 Ω - 14.4V. Targeted specifically for subwoofer applications, the JX250/1D includes a low-pass filter with continuously variable cutoff frequency selection from 50-200 Hz.
eBay