The OEM Cardinal SuperLife EasyOpen Binder with Locking Slant-D Rings is designed for heavy-duty use and features One-Touch EasyOpen rings that open, close, and lock with one simple motion. The Slant-D rings hold 25 percent more than standard round-ring binders, allowing for efficient storage of documents. With a 4-inch capacity, this binder can hold up to 775 letter-size sheets, making it ideal for extensive reference materials. The dual-fold living hinge ensures durability, while the transfer-safe, PVC-free polypropylene protects your documents from damage.