Easy installation and simple operation. High Quality 100% BRAND NEW High quality rotary switch. Hot-swappable (no need to reboot computer). Compact and super mini size; Easy to place and suitable for your desktop and office. Plug and play; No power supply and other software required; Won& 39;t affect sound quality. Analog signal maximum support 2V p-p input and output. Input and output frequency range: 20Hz ~ 20KHz. Use standard audio cable, input transmission distance up to 8 meters, output transmission distance up to 8 meters. Super small size; Compact and super mini size; Easy to place and suitable for your desktop and office. Main functions: Select audio input between (IN/OUT)A/B/C/D with 1/4 switch knob and get one output; Select audio output between (IN/OUT)A/B/C/D to receive one input; How to use: connect 4 audio sources (like CD player / computer/Phone/MP3) to 1/4 ports and 1 audio output (like speakers) to IN/OUT port; connect 1 audio source to IN/OUT port and 4 audio outputs to 1/4 port. Note: Only three-segment headphones are supported (four-segment headphones are not supported) Only one input can be played at a time.