Carstens Heavy Duty Ring Binders are made from premium Copolymer Polypropylene plastic to resist tearing and bending in even the most demanding work environments. The No-Gap steel rings are tested for over 50,000 uses right in our manufacturing facility to ensure they hold tight and stay aligned. The 3-inch ring models hold up to 400 sheets, 2-inch models hold 300, 1.5-inch models hold 250, and the 1-inch models hold 125. Our waterproof binder surface is impenetrable to air and liquids, ensuring easy cleaning and maintenance – ideal for rigorous use in busy environments. Whether it's for medical charting, healthcare facilities, offices, schools, or homes, Carstens Heavy Duty Ring Binders are built tough to get the job done. For over 130 years, Carstens has been the choice of the pros, setting the standard for quality and durability in products for healthcare facilities and beyond. We're proudly made in the USA of US and imported parts, and a WBENC certified Woman-Owned Small Business.