Headphone Amplifiers descriptions： We use high-quality raw materials, all materials are very suitable for the product, please rest assured to buy. Ultra-compact, 4 Channels, Stereo Headphone Amplifier With Power Adapter. Features: 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: 1.Input Type:LINE IN (O IN) 2.Output Type:LINE OUT (O OUT) 3.Built-in Battery:No 4.Recommended Headphone Maximum Impedance:65-80 Ohm 5.Type:Mini Amplifier 6.Model Number:HA400 7.Bluetooth:No 8.WIFI:No 9.Power Adapter:EU Plug 10.Plug Type:EU Plug,it Applies to Indonesia,Germany,France,Spain,Italy and So On. 11.Item Size:Approx.10.5 * 5.5 * 4.5cm/4.1 * 2.2 * 1.8 Inch 12. Item Weight:185g/6.5oz 13.Package Size:22.5 * 14 * 8.5cm/8.9 * 5.5 * 3.3 Inch 14.Package Weight:385g/13.6oz 15.Colour:Black 16.Material:Metal Package Contents: 1* Amplifier 1* Power Adapter 1* English Manual Only the Above Package Content, Other Products Are Not Included. . Products number : SOMONO94876