Feature Ultra-compact stereo headphone amplifier for studio and stage application. With 4 headphone output channels and 1 input channel. The volume of each output channel can be controlled independently. Provides the highest audio quality for each headphone even at maximum volume. Ultra-low noise 4580 operational amplifiers for outstanding audio performance. Comes with a DC 12V power adapter. Specification 100% brand new Voltage: 12V Voice Configuration: 4580 Size: approx. 104 x 57 x 50 mm Color: Silver/Black Package included 1 * Headphone Amplifier 1 * Power Adapter 1 * User Manual Note: 1. We don't offer a retail package, but we will pack it well before shipped out. 2. Please allow 0-1cm error due to manual measurement. plz, make sure you do not mind before you buy. 3. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!