8-Channel Monitoring Multi-Channel Headphone Amplifier For Recording Studio, US Plug 1. Material: metal 2. Input type: LINE IN (O IN) 3. Output type: LINE OUT (O OUT) 4. Built-in battery: None 5. Recommended headphone impedance: 65-80 ohms (MAX) 6. Type: mini amplifier 7. Power adapter: US standard 8. Ultra-compact stereo headphone amplifier for studio and stage applications. 9. 8 headphone output channels and 1 input channel 10. The volume of each output channel can be controlled independently 11. Ultra-low noise 4580 operational amplifier with excellent performance 12. Comes with DC 12V power adapter 13. Product size: approximately 19.6x5.7x3.1cm 14. Product weight: 350g Packing list: Amplifier x 1 Power adapter x 1 English manual x 1 Only the above package contents, other products are not included Note: different lighting and monitors may cause the color of the item in the picture to be slightly different from the actual item, measurement tolerance is +- 1- 3cm