Nail files are graded according to the grit per square inch. The numbers refer to how course the grit is on the nail file surface. If both numbers are the same then both sides have the same grit- if the two numbers are different then both sides have different grit. For example, a 180/180 grit file means both sides are the same and that there is 180 grit on 1square cm The higher the number, the softer the file grit; The lower the number, the coarser the file grit 80 grit: Extra coarse Used for heavy product removal or for shortening artificial nails faster. 100 grit: Coarse Used to take the length down and to shape side walls and free edge 180 grit: Fine Use to contour the whole nail; to prep natural nail before applying any product, also during manicure to shorten or shape natural free edge, and give a beautiful shape and nice, smooth finishing to artificial nails
