Goldstar carries nickel plated Metal Opening O-Rings (sometimes called 'Binder Rings'), in three different sizes: 1 inch, 2 inch, and 3 inch. The metal opening O-rings are sized according to the inside dimensions. Metal opening O-rings are most often found on school notebooks. However, those rings are also typically spring loaded. goldtstar' metal opening O-rings are not spring loaded and work great as key rings, mobile Rolodex flippers, quick release connectors between runs of webbing. Other uses include: swatch books, carpet sample books, color reference charts, and display hanging rings.