SNI-15 converts 10 to 30 watts per channel with a fixed 10:1 conversion, linear from 20 - 20,000 Hz at +/- 5 dB, while maintaining signal phase. Isolates input and output circuits to prevent ground loop noise. Perfect when adding an amplifier to a factory or aftermarket radio. Great for getting an additional set of pre-amps outputs from a head unit equipped with only one set.