features: 4 Ω bridgeable capability (DBA 80.4) | Trimode capability | continously variable12 dB boost on bass equalizer | continously variable 12 dB per octave highpass and lowpass crossover (DBA80.4) | continously variable12 dB per octave lowpass crossover DBA 1600.1D) | direct connect integrate speaker and power wire terminals | DC-DC PWM power supply | bipolar outputs| buffered preamp input circuitry | drink sink heat management system | buffered line out for easy Daisy chaining (DBA 1600.1D) | included bass |