Heavyweight Casebound DublLock Round Ring BinderVinyl is reinforced with heavyweight board that stands up to the toughest use. Heavy-duty round ring mechanism holds contents tightly in place. No ordinary casebound ring binder, this heavyweight storage giant holds its shape—even when subjected to rough, constant use. Equipped with DublLock® locking round rings to secure sheets without gaps. Three rings with metal hinge construction for extra-strength durability. Capacity Range [Min]: 0"; Capacity Range [Max]: 3"; Sheet Capacity: 480; Color(s): Black.