Indicated for fingernails and toenails, file on the medium grain side (180) and outline the contour on the fine grain side (220).
A high grit number (280-220) means that it is made up of many but very small grits, so filing is smoother. And a low grit number (120-180) indicates that the grain is thicker, recommended for shortening or initial filing.
How to use
File following the natural shape of your nails and always in the same direction. If you want to get a square point, keep the file perpendicular and straight.
If you prefer a rounded or oval finish, place the file at an angle below the free edge of the nail and file the corners well.