The CX 300.4 Four-Channel Amplifier is built to power all your door speakers in a small, powerful package. Using a Class D power plant, this amp features a variable bass boost with KickEQ™, giving you as much as a 12dB of extra bump. A powerful 12dB crossover is included, letting you quickly tune your system to perfection. Use the full range outputs to expand your system with a full range amp to complete your system.