It’s the guts of 3.5" floppies, like these, they usually stored 720kB, then 1.44MB, but the latest versions (double sided) were 2.88MB.

The larger one at the bottom is from a 5 1/4" (orange in this picture, the bug daddy in the picture is 8", first type I used, with COBOL)

… and now you kids know where the “save” button icon came from.

First game I ever played was on those 8” floppies. It was a turtle game where you would type in DOS commands and make it move. I can’t remember the command prompts but it was fun enter like forward 1000 and it would blast across the screen.