MIDI hardware - use this interface to connect your MIDI keyboard to any Mac or Windows computer with a USB port. 16 channels; 1 in and 1 out; comes with cable to plug into your computer's USB port *and* the cable needed to connect the interface box to your MIDI keyboard. Approx. 9-1/2 feet total length. A great, affordable choice for a MIDI interface! M-Audio UNO USB-MIDI Interface Features: 1-in/1-out MIDI interface 16 MIDI input channels 16 MIDI output channels Bus-powered---requires no external power supply Extremely compact and lightweight for mobile or desktop use Built-in USB and MIDI cables Computer System Requirements: Windows Windows 98SE, ME, 2000 (SP4),;XP (SP2)*, Vista (32 bit) *Home and Professional Edition Only. Windows Media Center Edition is not supported. Mac OS X 10.1.5, 10.2.8, 10.3.6, 10.4, 10.5.1 Specifications:Size: 3-1/2" (w) x 7/8" (h) x 1-13/16" (d) x 116" (cable)Weight: .075 lbs.