Item Type: Headphone Amplifier Material: Metal Plug Voltage: 100-240V Input: Type: 1/8in TS Connector, Stereo Impedance: 100k Maximum Input Level: + 15dBu Output: Type: 1/8in TS Connector, Stereo Impedance: Approx. 80k Maximum Output Level: Approx. 40mW in 100 Package List 1 x Headphone Amplifier 1 x Power Adapter 1 x Instruction Manual 1METAL MATERIAL: This small headphone amplifier is made of premium metal material that is rugged and durable for long lasting use. 2LOW NOISE: The low noise 4580 op amp ensures excellent sound performance and the high power stereo amplifier ensures maximum sound quality at maximum volume. 38 CHANNEL: Headphone amplifier features 8 independent channels, each switchable, with adjustable volume for each channel. 4INDEPENDENT CONTROL: 8 monitoring devices can be used at the same time, each device has an output volume control, easy to adjust the ideal monitoring volume. 5COMPACT AND PORTABLE: This stereo headphone amplifier is designed to be very compact and portable for use anytime and anywhere.