Need an amplifier that is built to last? Go for Diamond Audio D300.4. The Diamond D300.4 4-channel amplifier sends 50 watts RMS of clean, pure music to each of your vehicle's front and rear full-range speakers, with no audible colouration or distortion. Bridge this versatile amplifier to 2-channel mode to run a pair of subs, or you can set the rear amplifier channels into bridged mode to run a subwoofer with 150 watts RMS of bass, while still sending 50 watts to each of your front speakers. The focussed mass heatsink draws heat away efficiently by attaching 75% of its mass directly to the components that create the most heat. The amplifier's output transistors also mount to the heatsink using a special system that provides better heat flow than commonly used clips. The D300.4 features separate high and low pass filters and bass boosts for the front and rear channels, so you can tune it for a wide variety of specific speaker and sub systems. A pair of preamp outputs makes it easier to add a sub amp when you want, without having to run a new RCA cable to the receiver. And you will find speaker-level inputs for hooking the amp to a factory stereo that doesn't have RCA outputs.