It is a passport size dot grid refill.
The small dots printed at intervals of 5 mm are characterized as being very inconspicuous and difficult to obstruct while serving as a convenient guide when drawing sentences and drawing as well as when drawing graphs and frames is. Look like cartoons and frames, magazine articles and layouts, and you can count letters like manuscript paper, and look for unique uses of dots.
Since original writing paper (MD paper) in pursuit of writing is used, it has become difficult to bleed or fall through even with a fountain pen.
MADE IN JAPAN