A ring binder is a type of folder used to organize and store loose sheets of paper. It features a mechanism with metal rings that can be opened and closed, allowing users to add or remove pages easily. Ring binders come in various sizes and materials, making them suitable for different purposes, such as schoolwork, office documents, or personal projects. These binders often have a cover that can be customized, allowing users to insert labels or designs. Commonly used in schools and workplaces, ring binders help keep documents neat and accessible, promoting better organization and efficiency.