4 MIDI inputs and 4 MIDI outputs (64 MIDI channels).Perfect MIDI timing. High-speed connection to USB-equipped PC or computers. USB-powered, required no external power supply.Mini compact portable size. Can switch among USB mode and 4 Through modes.Compatible with XP, Vista, 7 and OSX or better. True plug-n-play, you do not need to install driver for XP, Vista, 7 and OSX. Colour:Black Material:Iron Package Contents: 1 x MIDI Box 1 x Cable 1 x English instruction manual Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.