Kenwood KAC-821 is a stereo power amplifier designed to deliver high-quality audio in your vehicle. It features a maximum power output of 140W per channel at 4 ohms, providing ample power for driving speakers or subwoofers. The amplifier has a built-in subwoofer frequency control, allowing you to adjust the low-pass filter frequency for optimal bass response with your subwoofer system. Additionally, the input sensitivity control lets you match the amplifier's input level to the output level of your head unit or other audio source, ensuring a properly balanced and distortion-free sound.