1) Ring shape: R(O), D, Q, A; 2) With ... 12 years in manufacturing; 5) OEM · Loose-leaf ring metal ring binder is usually used in folder production. We provide different ... types of metal ring binders according to numbers of rings. For example, 2 ... ring binders, 3 ring binders, 4 ring binder…etc. · More than 10 years in ...