Heavyduty reference binder features OneTouch EasyOpen rings that open, close and lock with one simple motion SlantD rings hold 25 percent more than standard roundring binders Backmounted steel rings reduce wear and let pages lie flat 4 capacity holds up to 775 lettersize sheets DualFold living hinge does not crack and break down Transfersafe polypropylene will not damage photos or your lettersize documents SuperLife EasyOpen Locking SlantD Ring Binder also includes exposed rivets and selfadhesive spine labels for easy identification