Description:   Ultra-compact stereo headphone amplifier for studio and stage application.   With 4 headphone output channels and 1 input channel.   Volume of each output channel can be controlled independently.   Provides highest o quality for each headphone even at maximum volume.   Ultra low noise 4580 operational amplifier for outstanding o performance.   Comes with a DC 12V power adapter.   Specifications:   Input Type:LINE IN (O IN)   Output Type:LINE OUT (O OUT)   Built-in Battery:No   Input Channels：1 Input   Output Channels：4 Output   Analog Inputs：1 x Stereo   Analog Outputs：4 x TRS   Recommended Headphone Maximum Impedance:65-80 Ohm   Type:Mini Amplifier   Model Number:HA400   Bluetooth:No   WIFI:No   Power Adapter:EU Plug,US Plug,UK Plug   Item Size:Approx.10.5 * 5.5 * 4.5cm/4.1 * 2.2 * 1.8 inch   Item Weight:185g/6.5oz   Package Size:22.5 * 14 * 8.5cm/8.9 * 5.5 * 3.3 inch   Package Weight:385g/13.6oz   Colour:Black，Silver   Material:Metal   Package Included:   1* Amplifier   1* Power adapter   1* English manual   Only the above package content, other products are not included.   Notes:   Note: Light shooting 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.