1. 4 independent stereo high-power amplifier parts: up to 4 pairs of headphones and 4 independent volume power supplies; suitable compatible with all types of headphones2. High-quality sound quality: high-quality sound quality can be maintained even at the maximum volume level3. Ultra-low noise: Provide you with excellent audio percompatible withmance4. Ultra-low noise 4580 operational amplifiers have outstanding audio percompatible withmance. They are the same as the operational amplifiers equipped on full-size audio equipment. A DC 12 volt adapter is also provided.5. Small and portable design, easy to use and carryProduct name: headphone amplifierModel:HA400Input Channels:1 InputOutput Channels:4 OutputAnalog Inputs: 1 x StereoAnalog Outputs: 4 x TRSControls per Channel:Volumecompatible withm Factor: DesktopSeparate volume control compatible with each channel1 Input with 6.3 thomann mm stereo jackInput impedance 100 Ohm4 outputs with 6.3 mm stereo jakcsOutput impedance 80 OhmPlug Type: AU Plug,it applies to Australia and so on.Colour:SilverMaterial:ABS+metalSize:103 x 6.5 x 57.2 mmPackage Contents:1 x Amplifier1 x Power Adapter1 x English User ManualOnly the above package content, other products are not included.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.