It is a triangular hand tool that is made of a hardened steel bar with good grip of handle. It’s three filing surfaces are cut with sharp, parallel teeth. These corrosion-resistant files work in spots others can’t with little to no clogging. They have two sets of diagonal teeth. It’s files are also known as American-pattern and machinists’ files, and are used to remove material quickly. Precision files which are also known as Swiss pattern files, are made to exacting measurements to ensure smoothness and are useful for finishing delicate and intricate parts. As it removes surface imperfections resulting in a precise, flat finish at a microscopic level. Achieving the flattest finish may require multiple steps using progressively higher grits or lower micron ratings.