Warm Tips: Not connect VU3 to amplifiers whose actual output power is greater than 300W, or else VU meter may be damaged. When power VU3 off, Amplifier B channel and Speaker 2 channel will be auto selected and can input and output audio signal normally. And when power VU3 on again, it will auto switch to the channels that are set before. Parameters: Audio input/output: 2 groups of banana female Working mode: 2-IN-1-OUT / 1-IN-2-OUT Amplifier type supported: all kinds of type (BTL /Class A /Class AB /Class B / Class D digital amp / tube amp etc.) Max. through power of each channel: 300W (in actual) Backlight brightness adjustment: 4-level adjustment (can be turn off) Amplifier no-load protection: support Remote control function: supprt Settings saved after shutdown: support Working voltage: DC 5V (above 1A) Power interface: Type-C Diameter of VU meter: 60*35mm Dimensions(W*D*H): 178*118*68mm / 7.01*4.65*2.68in Package dimensions(W*D*H): 280*185*155mm / 11.02*7.28*6.10in Net weight: 980g / 2.16lb Package weight: 1.2kg / 2.65lb Packing List: 1*VU3 VU Meter & Audio Switcher 1*Remote Control 1*USB Cable 1*User Manual