Feature: 1. Stereo 2 Input 4 Output: 4 ways stereo mixer board can directly push four headphones or external amplifiers without affecting each other. Inputs and outputs are 3.5mm. 2. Volume Adjustment: Each track of the 4 way sound mixer board has an independent volume adjustment knob for the output through headphones and speakers. 3. Basic Parameters: The power supply is DC5‑15V, the amplification is 5x (14dB), and the potentiometer controls the volume of each output separately. 4. High Current: JRC high current op amp NJM4556A is used, with a maximum output current of 70mA, which can provide good large dynamic fidelity output. 5. Plug and Play: Amplifiers mixer distributor is the perfect way to listen to music and mix multiple sound sources, including smartphones, tablets, computers, MP3 players, CDs and more. Specification: Item Type: 4 Ways Stereo Mixer Board Material: PCB Size: Approx. 119 x 50mm/4.7 x 2.0in Input: 3.5mm Output: 3.5mm Voltage: DC5-15V. Package List: 1 x 4 Ways Stereo Mixer Board6 x Knob1 x Sound Cable Note: The unit can also be used as a 1 / 4 out stereo splitter box when all controls are rotated fully clockwise.