I was having issues with only my front speakers in my car. They were giving me a little feedback from the alternator. I have been into car audio for about 7-8 years and I know how to ground amplifiers quite well. I tried everything and could not get a solution. So i ordered this product and it eliminated any engine/ alternator noise and actually cleaned the signal up nicely.

I didn't think I'd be able to squelch the noise coming from my iPhone when playing music through a DVD connect in my car - but this product did the trick! Fantastic value. For people who don't have an iPod connector but have to use RCA, this is the thing.