Converts the speaker levels of a factory or aftermarket radio to RCA while giving the user remote control over the amp volume; Allows user to add a trunk-mounted amp ;for subwoofers; Provides an additional set of preamp outputs from a head unit equipped with only 1 set; Allows more control over a system’s sound; Adjusts head-unit output from 2W-40W per channel ; Mounts in dash or under dash;