You probably don't even remember floppy disks anymore. You probably think of them as the "save" button on most software.
However, they were once a big deal. The 3.5-inch disks were the main way we moved data around before CDs or DVDs became a thing. They could only hold 1.4MB.
Believe it or not, there were still millions of floppy disks sold up until a few years ago. Sony was the last to stop manufacturing them in 2011, even though just in 2009 they had sold 12 million of them!