Eliminate hiss, buzz and other background interference caused by ground loop noise. Designed to improve sound quality on car stereo systems and home speaker systems when the audio source is physically connected by 3.5mm audio cable. Filters out noise instantly for clear, uninterrupted, uncompromised sound. Lose the noise; keep everything else. Plug and play, no battery needed, no direction limited, just plug one jack as input, the other is output. Work with any portable device that has 3.5mm audio jacks. Compatible with most Bluetooth car kit or Bluetooth receiver for your home/car stereo system.