Abrasive is a material used to roughen, shape, polish, or remove the surface of artificial and natural nails; or one component of a file (the abrasive material is affixed to a core, which is usually affixed to a cushion or center). Abrasives are one of the most-often used tools by nail techncians — for shaping, removing shine, and smoothing. They are also used for every type of nail treatment, from natural manicures to application and fills of acrylics, gels, and wraps. Nail files come in a myriad of sizes, colors, styles, and grits. Files can have different grits on each side — some files feature up to four different grits. (Grit is the measurement of coarseness of an abrasive. The lower the number, the rougher the square. A 100-grit abrasive means that 100 pieces of abrasive material cover a 1-inch square. A 240-grit squeezes 240 smaller bits of abrasive material into that same 1-inch square, making the higher numbers much finer.) Coarse abrasives are used to shape artificial nails and remove acrylics and gels. Finer abrasives are safer for natural nails and are used to smooth artificial nail surfaces. Cloth and chamois buffers are used to smooth and shine natural and artificial nails. While some salons use metal nail files, which must be disinfected after each use, the majority of salons use disposable nail files. The files shown in the photo are from Soft Touch, one of the industry's largest makers of files.