Reduces noise mixed into RCA lines. Effective mainly against noise synchronized with engine speed. When connecting two or more devices (such as a head unit and an amplifier), current can flow through the RCA cables, which should ideally only carry the signal. This can cause noise. This is because potential differences can arise due to differences in the connection points of the power supply and ground. The NF120 blocks unwanted current flowing through the RCA cables, and reduces noise by allowing only the signal to pass through. Please use it after understanding the basics of grounding at the same location. Package Contents ・Stereo RCA Noise Filter 1 piece ・Size: L70xH30xW34mm #HamuesuAudioParts #HamuesuRCAcable ＜＜About Shipping＞＞ ・Yu-packet Orders paid in the morning will be shipped the same day, but we are closed for shipping on Saturdays, Sundays, and holidays.