Know what this is?
Back in the age of paper, notebook-hole punches were more prevalent than flip charts.
We were naive enough to believe we could capture tacit know-how on sheets of paper in three-ring binders.
Even if the main part was already punched, you had to punch the addendum, errata, schedule changes, and so on by yourself.
In those days, people took binders to classes, where they underlined and highlighted and highlighted the text. When they got back to work , they did so with confidence that they could look up and figure out whatever they needed.
The binders went onto bookshelves to gather dust for six months.
The one time you pulled down a binder to look something up, it wasn’t there. Not even the subject.
I have purchased more than 250,000 3-ring training binders in my career. (Sorry, Planet Earth.)
If you didn’t recognize the 3-hole punch, you are better off.