Warm Tips SP-220S version has a volume control knob, can adjust the audio source volume Features 2-IN-4-OUT Audio selector, the input can be connected to 2 amplifiers, and the output has 4 interfaces, which can be connected to speakers.The panel has Push-Button input and output switching buttons, manual switching, stable sound without interference no need to plug in, easy to use and save energy.There is a non-slip pad at the bottom to protect your desktop using audio equipment with a switch can avoid the wear and tear of the interface caused by plugging and plugging, and prolong the service life of the audio equipment.Parameters SP-24B Version Audio input: Stereo RCAx2 Audio output: Stereo RCAx4 Dimensions(WxDxH): 160x120x40mm or 6.30x4.72x1.57in Net weight: 270g or 0.60lbPackage weight: 500g or 1.10lb SP-24 Version Audio input: Speaker jacksx2Audio output: Speaker jacks x4 Dimensions(WxDxH): 160x120x40mm or 6.30x4.72x1.57in Net weight: 270g or 0.60lbPackage weight: 500g or 1.10lb SP-220S Version Audio input: Stereo RCAx2 Audio output: Stereo RCAx4 Dimensions(WxDxH): 143x160x62mmPacking List1xSpeaker Selector Box