Warm Tips: The SP-220S version features a volume control knob, allowing you to adjust the audio source volume. Features: 2-IN-4-OUT Audio Selector: Connects 2 amplifiers to the input and 4 speakers to the output. Push-button switching: Manual switching on the panel ensures stable, interference-free sound. Plug-and-play: No power required, easy to use, and energy-saving. Non-slip base: Protects your desktop and prevents wear on audio equipment interfaces from frequent plugging/unplugging, extending their lifespan. Parameters: SP-24B Version: Audio Input: Stereo RCA*2 Audio Output: Stereo RCA*4 Dimensions (W*D*H): 160*120*40 mm / 6.30*4.72*1.57in Net Weight: 270g / 0.60lb Package Weight: 500g / 1.10lb SP-24 Version: Audio Input: Speaker Jack*2 Audio Output: Speaker Jack*4 Dimensions (W*D*H): 160*120*40mm / 6.30*4.72*1.57in Net Weight: 270g / 0.60lb Package Weight: 500g / 1.10lb SP-220S Version: Audio Input: Stereo RCA*2 Audio Output: Stereo RCA*4 Dimensions (W*D*H): 160*120*62mm Packing List: 1*Speaker Selector Box