[ Stereo Audio Mixer ] 4-Channel Audio Mixer Can Mix 4 Stereo Audio Signals Can Mix Mixing Instrument, CD Player, Tape Player, Computer, Mobile Phone, Tablet Audio Signals to Speaker and Headphone. [ Input and Output ] With 4-Channel (L&R) Input and 1-Channel (L&R) Output, Convenient to Use. [ 4 Separate Volume Controls ] Each Channel Has an Volume Control, Adjust the Volume as You Needed. [ No Need Power Supply ] No Power Supply Requirement. Plug and Play, Metal Housing, and Sturdy. [ Ultra Low Noise ] Better Sound Quality Even at Maximum Output Levels, Provide an Excellent Audio Performance. Specification: Input impedance: 10K ohms to 47K ohms Output impedance: 2.5K ohms to 10K ohms Gain: -12dB MAX Product net weight: 0.2 kg Product size: 85 mm X 52 mm X 40 mm Colour:black Material:Metal Size:8.5 x 5.2 x 4cm Package Contents: 1 * Stereo Audio Mixer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.