M-Audio MIDISPORT 4x4 Anniversary Edition | 4-in/4-out MIDI Interface (64x64 discrete channels I/O via USB)<div style="text-align: left;"><strong>[Product Information]</strong><ul><li><span class="a-list-item"> 4-in/4-out MIDI interface (64 discrete MIDI input channels， 64 discrete MIDI output channels) </span></li><li><span class="a-list-item"> Connection and power via USB， requires no external power supply </span></li><li><span class="a-list-item"> Class-compliant operation under Windows XP， Windows Vista and Mac OS X， no additional drivers required </span></li><li><span class="a-list-item"> MIDI activity indicator for each port </span></li><li><span class="a-list-item"> Compact and lightweight for mobile or desktop use </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/41FRLSj35xL.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/31fW9n88smL.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/31vpOOrbY1L.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/419xFl8qC1L.jpg" noproxy>