I am lucy my E-mail zx032005@163.com MSN :musicsurces1@hotmail.com.cn Front RCA Inputs Front Gain:Adjusts the input sensitivity Front Bass Boost:Adjust bass equalization from 0 to +18 db Front Crossover: Control and switch sets the mode and frequency. Front Speakers: Connect a single 4Ω load across the contacts for 220 watts bridged output. Power: Connect heavy (8 guage min) stranded wire to the 12 volt and ground source. Connect the ground to the auto chassis near the amplifier. Fuse: Never replace with a fuse greater than 25 amplifier each. Rear Speakers: Connect a single 4Ω load across the contacts for 220 watts bridged output. Rear Crossover:Control and switch selects mode and frequency Rear Bass Boost: Adjust bass equalization from 0 to +18 db Rear Gain:Adjusts the input sensitivity Rear RCA Inputs