Slant-D® rings allow sheets to turn smoothly. Holds up to 50% more than conventional round ring binders. Super-strong, heavy-duty construction for frequent use. Stands up to years of use with the XtraLife®Hinge. Locking Slant-D® rings secure binder contents and keep ring wires aligned. Expand-A-Pocket® in back expands to hold up to 1/2" stack of materials. Exclusive DataGuard™ Pocket inside front prevents document damage. BlindEdge™Weld for even more durability.