Reference binder features back-mounted rings for a clean professional spine. XtraLife hinge provides durability. Back-mounted design allows sheets to lie flat. Steel, nonlocking round rings also have dual opening and closing triggers for easy sheet removal and insertion of your letter-size papers. 1 ring capacity accommodates up to approximately 225 letter-size sheets. Two horizontal pockets on the front and back covers secure loose, unpunched documents. Each pocket holds 40 sheets. Design also includes exposed rivets and a sturdy chipboard core. Binder is made with a high percentage of recycled post-consumer material."CRD72712. 72712. Cardinal Cardinal BasicSelect Binder with Round Rings.