I bought this to reduce line noise from my Galaxy Nexus to my car stereo. It had an annoying buzzing, and the filter completely removed all traces of it. It comes with a length of cable, so it isn't a matter of just plugging both ends into the box. I could see as being a con or a pro. It didn't hinder me any.

Perfectly satisfied, a little pricey for what it does.

I used this to boost the sound for my outside speakers on my RV. I plug my iPod directly into the amp. Even with the $5 speakers that came with the RV , sound imprpovement was fantastic. Inexpensive and worth it to me.