Durable material: The equalizer features a high quality metal housing and operates on 12 V DC. It has a premium look and feel, is easy to use, and built for long life. Six channel outputs: This 9-band equalizer supports front left and right channels, rear left and right channels, and two subwoofer outputs. The independent subwoofer output and the adjustment function enhance the car audio experience. Nine bands and features: The auto audio equalizer provides 9 equalization bands (50 Hz, 100 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz, 16 kHz), intelligent noise suppression, precise adjustment, and the subwoofer frequency can be set from 30 Hz to 120 Hz. Two channel inputs: The auto audio equalizer supports CD and Aux inputs with a gain control to adjust the Aux volume, delivering better sound quality. Use scenarios: - In-car upgrade: balance front and rear channels and add subwoofer output to improve overall sound in a sedan or SUV. - Sound tuning: enthusiasts can precisely adjust frequencies across the spectrum for various music genres. - Flexible sources: convenient CD and Aux input support with gain control to optimize Aux playback in everyday driving.