Check the listing for details. Ensoniq SD1 Operating System Disk v4.10 Sequencer OS - SD-1 FASTEST SHIPPING!. Condition: New. Listed at 12.00 USD. Ensoniq SD-1 Sequencer OS Operating System Disk v4.10 NEW DS DD 3.5" disk. Includes:OS Boot Disk v.4.10 ______________ OS Boot Disk v.3.0 is available upon request.______________ ________________________________________________________________________________________________________________________________OS v4.10 requires a ROM version 4.00If you have a lower ROM Version than 4.00, then you need the v3.00 OS diskYou can determine which firmware version you have by pressing and holding the Presets button, and while holding it down, press the Master button. The "ROM V #.##" message on the second line tells the firmware version. Message me for v3 OS Disk.________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Check out my other auctions for OS Disk, CD & DVD Drives, Hard Drives, and Sample Disk.