1、Metal Material: Headphone amplifier is made of metal material, strong and durable, ultra compact design for easy carry. 2、4 Channel Stereo Headphone Amplifiers: It has 4 headphone output channels and 1 input channel with excellent sound quality. 3、Independent Control: The volume of each output channel can be controlled independently. Provides the highest sound quality for each earphone even at maximum volume. 4、Low Noise: The ultra low noise 4580 operational amplifier ensures superior sound quality. Enjoy a low noise monitor distribution and music system. 5、Widely Used: Ultra compact headphone amplifier system is for studio and stage applications, outdoor performance, mini concert, karaoke, conference speech. 1 x Headphone Amplifier1 x Adapter 1 x Instruction Manual Item Type: Headphone AmplifierMaterial: MetalWeight: Approx. 315g / 11.1ozVoltage: AC 100-240V 50Hz 60Hz