Connected to the device interface can be used, without external power supply, simple operation with output volume control, you can adjust the ideal monitoring volume according to your preferences The XLR input connection has a locking structure in case of accidental cable disconnection. Just press the label next to the bottom mounting connector to release the cable at Metal 3.5MM headphone output interface can be easily connected to conventional earbuds or professional monitoring headphones, bringing you a clear music experience Colour:Black Material:Aluminum Package Contents: 1x Headphone Amplifier 1x XLR Cannon connector 1x English manual 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.