Automatic Power On - the crossover turns on when you turn on the vehicle's autosound system (when it is connected to switched power lead).
Subwoofer Phase Shift Selector - lets you adjust the subwoofer to compensate for acoustic timing delays between speakers.
Bass Boost Control - lets you boost subwoofer bass output by 12 dB Subwoofer Input Selector - lets you select one-line or two-line input to match your autosound system's line output.
Midrange Crossover Point Selectors - let you set the midrange's lower crossover point to 50 Hz, 90 Hz, or 180 Hz for high frequencies,and its upper crossover point to 2kHz, 4kHz, or 6kHz for low frequencies.
High Pass Crossover Point Selector - lets you set the tweeter crossover point to 2kHz, 4kHz, or 6kHz.