Traditional rectangle erasers have only 8 corners. While, the unique shape of Kokuyo Kadokeshi 28-corner eraser allows it to have 28 corners. This is significantly greater number of corners which one piece of eraser can get. Hence, the large number of corners can provide more precise use of it. This feature is very useful for professionals like designers, architects and artists, etc. You can also pull off the block which is round out to get access to the next sharp corner. In addition, the eraser is latex-free and phthalate-free.