Ring binder

These are held in the binder by circular or D-shaped retainers, onto which the contents are threaded.

The binders themselves are typically made from plastic with metal rings.

American Henry Tillinghast Sisson invented a "new and useful improvement in portfolios and paper files" he called a "temporary binder."

German Friedrich Soennecken invented ring binders in 1886 in Bonn.

[4][5] Another design for ring binders was invented in 1889 by Andreas Tengwall in Helsingborg, Sweden, and patented in 1890 under the name "Trio binder", named after a business consortium of Tengwall and two associates.

The North American de facto standard spacing is 4.25 inches (108 mm) between holes.

"Ledger" size binders hold 11-by-17-inch (28 by 43 cm) paper, and may use standard 3-ring spacing or multiple additional rings.

[6] Many personal organizers and memorandum books use a six- or seven-hole system, including Filofax and FranklinCovey.

The sheet protector has pre-punched holes, so the document can be kept untouched and unwrinkled.