3 in 1 Function, combined with USB MIDI, Merge and Thru functions. 4 Inputs, 4 Outputs MIDI interface (64 MIDI Channels). MIDI Merge Function for mixing data from inputs 1 and 2 to output 4. Perfect MIDI timing, USB powered (no external power supply required). High-speed connection to USB-equipped PC or Mac computers. True Plug and Play & wide compatibility; no driver installation required. Mode SW: USB and MIDI Thru mode switch button. This button allows you to select one of the 5 operating modes of the interface (one USB mode and four MIDI Thru modes). With this MIDI Box, you can achieve accurate MIDI timing and reliable performance at an affordable price. Compatible with Windows XP, Vista, and Mac OS X or later. MIDI In and MIDI Out activity indicators for each port. USB powered (no external power supply required). Material: Metal Color: Black Package Contents: 1 x MIDI box 1 x cable 1 x English manual Only the above package content is included; other products are not included. Note: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement error allowance is +/- 1-3 cm.