This item is supposed to reduce signal noise on your rca cables as it is a ground loop isolator. Only thing is that it not only eliminates the noise but takes the music with it. There a little adjustment screws on the top for a left and a right, when adjusted you can choose how much signal you want to go through. Seems like noise and music or nothing, not really an in between. Also it was put together very cheaply and one imput shakes loose when moved so this has to be used for home use only and drilled in place. I had probelms with signal noise in my car stereo every time i accelerated the noise went with the engine. Tried various ground loop isolators (none do the job) and was able to reduce the noise by redoing my ground with a 0 gage cable and properly soldering and bolting to the chasis. Also use Dayton rca cables, they are a little pricy but cheaper than monster by far and the best quality rca's ive seen really heavy duty fat cables. Don't get ripped off with monster brand, buy the daytons. The Rca's made a huge difference and no more signal noise (now i dont even use a ground loop isolater and if your system is wired properly you shouldn't need one either)