The Stereo Audio Isolator is an audio common ground isolator that effectively suppresses noise caused by common ground issues between sound sources and receiving devices. Differences in grounding resistance can allow noise to enter electrical equipment via the ground wire, creating interference. When the grounding points of two devices differ, common ground noise can arise, particularly evident in car audio systems as audio interference, often described as a whistling sound that changes with engine speed. This isolator is designed to eliminate noise and current sounds generated by common electricity, but it cannot address noise caused by other sources, so it is essential to identify the origin of the noise yourself. Size: 13.5 x 3.35 x 0.67 inches.