Features: One input port of sound equipment can be extended to four interfaces through this machine. Four channel can simultaneously input mixed output, and the volumes can be adjusted independently. 6.5mm double cores interfaces, which can be connection with a moving microphones or musical instrument, with amplification function. Press the blue switches, and the magnification is about 5.6 times (15db). Built-in lithium battery can be used continuously for 8-10 hours when charging, and USB cable can be charging by using the mobile phone charging head. Suitable for musicians and sound engineer, blending instrument like guitars, basses, and keyboards with ease. Specifications: Component:Metal Size:Approx.115x68mm/4.53x2.68inch Package Includes: 1Pc Stereo Mixer note: 1.Please allow 1-2cm errors due to manual measurement, making sure that you not mind before order. 2.Due to the differences between different monitors, the picture may not reflect the actual of the item.