Features: 1. The Compact 4-Channel Stereo Headphone Amplifier Can Be Used For Up To Four Headphones At The Same Time, That Is, To Listen To The Main Mix At The Same Time With Separate Volume Control.2. Equipped With Four Powerful Stereo Amplifiers, Which Can Provide Excellent Performance At Any Volume.3. Clear Sound, Ultra-Low Noise 4580 Operational Amplifier For 19inch Studio Equipment.4. Individual Volume Control For Each Channel5. 1 Input 6.3 Toman Mm Stereo Jack1. Input: Impedance 1002. Output: 6.3mm Stereo Jack3. Output Impedance: 80Plug Type: US Plug, it applies to Canada, India, Mexico, Thailand, the , the Philippines, Taiwan and so on.voltage: AC100-240Vsize: 103 x 46.5 x 57.2mm( Width x Height x Depth )Material: ironcolour: blackPackage Contents:1 x Headphone Amplifier1 AdapterOnly 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.