Found this in a bunch of stuff I recently acquired. Brings back good memories. It’s a 3.5” magneto optical disk from the 90s. Magnitudes more reliable than other removable storage technologies with a lifespan of 30 + years. The 5.25” disks hold up to 9.4GB. I’ve only come across SCSI MO drives of these types but I believe Olympus made usb versions of the 3.5”. #retrocomputing#macintosh#opticaldisk#removablemedia