AtNeDcVh 2 Zone Amplifier Speaker Lossless Switcher Selector, 1 In 2 Out / 2 In 1 Out Amps Speakers Switch Control Box Splitter, 2 Way Stereo Audio A B Switches 2 Zone amplifier speaker switcher selector, 1 amp In to 2 pairs of speakers Out (1-In 2-Out), or 2 amps In to 1 pair of speaker Out (2-In 1-Out). A and B channels cannot in or out simultaneously. When you have multiple amplifiers or speakers, you can avoid frequently plugging and unplugging of wires to switch amplifiers or speakers. Lossless switching and stable transmission. Excellent circuit design, high-quality gold-plated banana sockets, providing you with the best sound. Knob switching for easy control and switching. No power required, plug and play. Dimensions: L 7.48in * W 6.3in * H 2.83in (L 19cm * W 16cm * H 7.2cm) What's in the box: AS-B21 2 Zone Audio Switcher *1 pcs Product Guide *1 pcs