Hasamu How to insert two pens in A4
Hasamu A4 pen holder holds only one slim pen.
If only one more pen would fit."
You may feel so.
In this case, you can carry two pens by inserting a pen into the bent part as shown in the photo. This also allows you to carry thicker pens that do not fit in the pen holder and prevents strong creases in the paper.
This may eliminate the need to carry a pen case.