... Superior quality FCC,CE,RoHS Short delivery time 4-in 4-out usb midi interface Model:W-819 Product Description4 input ... output ports, user choose the input port and output port in computer; 2. Can be used as MIDI extender, with ... port and 1 out port, 2 input port and 2 out port 3 input port and 3 out port, 4 input ... port and 4 out port; 3. ...