400W Class AB 4-Channel Thunder Series Car Amplifier. Upgrade your power for better sound. You'll get some serious MTX musical mojo when you put the MTX THUNDER75.4 4-channel amp in your car. This compact amp will drive each of your front and rear speakers with 75 watts RMS of detail-enhancing musical power. Install a nice set of speakers, and you'll hear sounds you've never heard before, even in your favorite songs. And this little bruiser will truly fit in places where amps don't usually go. Versatility You can also put this amp into 2-channel mode to drive two subwoofers with 200 watts RMS per channel. In 3-channel mode, you can run some nice components up front with two channels while running a sub off the third channel. Advanced tone control The crossover filters on the front and rear channels allow you to adjust the sound to your setup. The front channels use a variable high-pass filter to keep the bass away from your full-range speakers, so they play cleanly. The variable rear crossover can be set to high- or low-pass depending on whether you're running a subwoofer or full-range speakers on the rear amp channels. It also features a very wide range of crossover points, that'll be useful for tuning midrange and midbass speakers.