1) Deposit on a wedding band 2) German invention 3) Loose-leaf notebook 
Ring binders (loose leaf binders, looseleaf binders, or sometimes called files in Britain) are large folders that contain file folders or hole punched papers. These are held in the binder by circular or D-shaped retainers, onto which the contents are threaded. The rings are usually spring-loaded, but can also be secured by lever arch mechanisms or...
A binding with several metal rings that open to hold loose-leaf materials
noun holds loose papers or magazines