When you need extreme durability for a construction work site, industrial warehouse or heavy daily use by multiple associates, this 1-inch angle-D ring hardboard binder with aluminum hinge will meet your needs. It features 1/8-inch hardboard and nickel-finished angle-D rings that are riveted to the back panel. These types of rings allow a higher capacity of paper than standard round rings. This binder also has heavy duty continuous aluminum piano hinges and is finished with polyurethane spray, making it moisture resistant.