File fasteners are used most commonly for medical filing and office filing needs. Our basic prong fasteners are made of a durable tempered steel and can be used to file two-hole punched papers of many sizes. They come in multiple capacities, so you can use them for up to 3 ½" thick stacks of paper. That is the thickest binding capacity possible with any standard method. We also offer custom medical chart dividers, also called fileback dividers, in both paper and poly plastic materials.