Robust and easy to use
I am an author who prefers to write first draft manuscripts with pen and paper. Carrying A5 looseleaf paper in slim binders is a convenient format for works in progress, but a full novel will often produce hundreds of pages (a 3-inch stack!) of writing. These fat A5 binders hold all my work and allow for easy rearrangement of pages. The ingenious clamping system keeps the paper supported upright when the binder is stored on my bookshelf. I was previously using Japanese 2-hole post binders which were not as convenient.