This 11x17 Binder really is a unique product. This binder is ideal for Presentations, controlled environments, and archiving projects. Binder panels are made from an Extra-Thick Acrylic Plastic. The non-flexible smooth panels keep a rigid and sturdy surface. The flat spine is made from the same material as the panels. There is a 3" nickel finished Slant-D Ring, riveted to the back panel. The Slant-D Ring holds 25% more paper than a regular round ring. This binder is hinged on the 11" Side, with continuous aluminum piano hinges that are riveted to both panels and the spine.