Dimensions (wxhxd):104 X 57 X 50 MmBody Material:PlasticWifi:NoBluetooth:NoPcm:NoDsd (direct Stream Digital):NoOperational Amplifier Chips Model:-Dac Model:-Channels:4Package:NoOutput Power:-Type:Mini AmplifierRecommended Headphone Maximum Impedance:65-80 OhmBuilt-in :NoOutput Type:Line Out (audio Out)Input Type:Line In (audio In)Origin:Mainland Certification:CeFeature 1:Home AmplifierFeature 2:Ultra-compact Stereo Headphone AmplifierFeature 3:For Studio And Stage Application.Feature 4:With 4 Headphone Output Channels And 1 Input ChannelFeature 5:Volume Of Each Output Channel Can Be Controlled Independently