Wilson Jones Heavy Duty 3 Ring Binder with Extra Durable Hinge, 1.5 Inch Round Ring, 4-Pack, Black (W70364-34NBPP) 4 pack of our strongest binder covers and extra durable hinge for years of reliable use; 3 ring binder covers and spine will not rip apart; 1.5 inch round ring binder holds 350 sheets Never Gap Rings prevent papers from accidentally coming loose; all three rings close tightly every time you add or remove a page; custom formulated, PVC Free polypro material lasts up to 10X longer than vinyl Two interior pockets provide additional storage for loose sheets