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 engineered to hold tight, prevent gaping and stay aligned. The 4-inch ring models hold up to 600 sheets. Our waterproof binder surface is impenetrable to air and liquids, so nothing can grow beyond the surface – versus standard vinyl binders that can absorb liquids and harbor substances. This unique cover material ensures easy cleaning – 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 the long haul with a 3-year warranty on the covers and a 1-year warranty on the rings. 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.