These solve a different problem to a binder: a small set of cards, swatches or reference sheets that has to fan out and lie in any order. Diameter should exceed the stack thickness with room to spare, since a ring filled to capacity will not turn freely and the cards jam. Hinged rings open one-handed; welded rings hold shut better. See book rings, binding supplies and system cards.

Binding rings arranged on a bright office desk with training notes, sample cards, colour swatches and organised project materials.
Binding Rings for Organisation

Shop binding rings for loose pages, flashcards, samples, swatches, key sets and office organisation.