This Crunch PX 1000.4 4 Channel Amplifier and Crunch PX 1000.2 2 Channel Amplifier are perfect entry level amplifiers for your car audio needs. They have high quality circuit and hardware designs along with exclusive technologies to improve sound quality and minimize distortion. Crunch POWERX incorporates full Class A/B technology in stereo and 4 channel amplifiers along with Class D in the mono. Class A/B sounds better, but the PC boards require a bit more space that in other circuit topologies. With Crunch POWERX we have trimmed away some of the more esoteric features to deliver a great amplifier that sound like you would expect Crunch to sound. The POWERX line also includes Crunch technology like QTD (Quick Thermal Dispersion) Technology which puts more aluminum on the heatsink than a normal amplifier. QTD assures the amplifiers make huge power while running very cool with nearly undetectable musical distortions.