Features: Heavy duty metal binder rings with rustproof and break resistant coating ensures long time durability, solving the issue of brittle plastic rings breaking under frequent use. Large diameter designs enables single handed operate for quick document access, requiring easy assembly or adjustment. Suitable for students, office workers, and outdoor planners needing multifunctional heavy duty paper organization across mixed size project. Secures letter size or larger sheets effortlessly in binders or notebooks, widely used for classrooms, busy office, and humid environment. Crafted from metal to meet international safety standard, suitable for children art craft and archival document preservation. Specifications: Component: Metal Color: Silver Small Size: Approx. 70mm/2.75in Large Size: Approx. 80mm/3.14in Weight: Approx. 720g, 800g Package Includes: 30Pieces Metal Binder Rings note: 1.Please allow 0-1cm error due to manual measurement. Be sure you donot mind before bid. 2.Due to difference between different monitors, the picture may not reflect the actual color