【Noise 】Most switches cannot reduce noise. We have realized 【Usage 1】Switch between 4 playback devices and select 1 channel to play 【Usage 2】Switch between 4 groups of stereos and select 1 of them to play 【No External Power 】No power supply, no effect, no need to worry about affecting the sound quality after processing 【Small size 】It is the same size as a rubber, which can be conveniently put into your pocket, so that you can use it in any scene you want to take No Noise 4 way 1 in 4 Out or 4 in 1 Out Audio Sound selector RCA Female Stereo 4 Channel Splitter switcher Box Switching No External Power