The Case-it D-250 Zipper Binder is an organization machine for office and home use. This 3-ring organizer features 2-Inch O-rings to keep papers in place. Made of Tri-Lobal nylon for durability and to maintain your binder's good looks. A full mesh pocket on the outside and two inside pockets are perfect for calculators, rulers, extra papers. The D-250 also features a carry handle and shoulder strap for versatile mobility. The zipper has a unique angled design to make it easier and quicker to zip things up when packed with your important papers and materials. The D-250, like all of Case-It's binders, uses kraft board instead of PE board to give its binders a firm, stiff shape that won't buckle or warp. The spine is specially designed so that your binder can lie flat when open, making it easier to add or take papers out, and to take notes in. Case-It produces quality binders offering unique organizational tools for office and home use.