Share a Single Stereo Source: 4 channel amplifier features 4 independent stereo high-power amplifier sections with separate volume knobs for each of up to four outputs, which makes it possible for up to four people to monitor the mix for tracking, live uses and listen to the TV with earbuds while working out. For Studio and Stage Applications or more: Such an ultra-compact and portable design makes it very suitable for the studio or stage where multiple headphones are used at the same time. Fantastic Stereo Quality: It is a mini headphone amplifier with 3.5mm (not 6.35mm)input/output that contributes to the smoother connection of output and input, suitable for virtually all types of headphones, creating the highest Stereo audio Quality and eliminating the need for a 6.35 to 3.5mm adapter to connect the headphone power amplifier to the headphone. Unique Compact design with switch: It is convenient for you to turn on/off the compact headphone power amplifier with a power switch anytime and anywhere, saving energy when enjoying high stereo audio quality. What You G: Ultra low noise headphone amplifier*1,12V DC power adapter *1, Use manul*1, 18 Months Warranty for Fosi Audio Headphone amplifier. Please contact us at any time if you have any problems.