UNI-BALL MITSUBISHI Kurutoga High Grade Model Auto Lead BLACK 0.5 mm Pencil [M5-10121P.24] The Kuru Toga Series from Uni-ball Mistubishi has a core rotation mechanism that can automatically rotate the pencil lead as you write. The lead is twisted through a spring-loaded clutch, it works by twisting incrementally every time you lift the pencil up (i.e. during printing words, etc). This allows a uniform wearing of the pencil lead so that it always remains as a pointed tip. So you can easily avoid the usual problem of using pencils: 1. At first the pencil has a sharp point, but after that when you continue to write the point is worn down, and your line widths are smudgy and thicker. 2. Sometimes the tip of the angled point can scratch or catch on the paper. 3. The lead is easy to break due to some positions of the tip and the angles of the tip. But using Kuru Toga pencil, you will not have to face the above problems. You are effectively using only 50% of the lead area that you were previously using with your old mechanical pencil. Thus, a 0.3/0.5 mm Kuru Toga will write incredibly thin lines and have less breakage than a standard 0.3/0.5 mm mechanical pencil.