5.25" floppy drives were originally single sided which meant that only one side of the disk was used for storing data. It didn't take long for people to realize that the media makers put the same magnetic coating on both sides of the disks which meant that the disk could be flipped over and used. But, without a notch cut in the edge of the disk it was write protected while upside down.
A standard hole punch, scisors or a pocket knife could be used to create the appropriate notch, but these were crude solutions that didn't look good and could end up misplaced, potentially damaging the disk or sticking in the drive.
The solution was to get a flippy maker. This was a specialized punch designed to line up the disk and to produced the perfect notch for flipping.
I have several in my collection but this one is especially fun with a Pac-Man printed on it.
It even came with a bunch of vintage notches!