EDIROL (RolandED) SK-500 FreeMIDI USB Driver for MacOS For Product(s): SK-500 This is a driver for using the SK-500 with Mark of the Unicorn Corporation`s FreeMIDI when SK-500 and your computer are connected via USB cable. In order to use it, you will need to separately obtain FreeMIDI Version 1.35 or later. For Operating System(s): MacOS