There's a real problem that affects almost all mechanical pencils-bear with us as we explain. As you use a regular mechanical pencil, the lead wears down on one side, forming a slanted wedge-shaped tip. Each time you put the lead to the page you end up using a different lead surface (pointy, flat, wide, thin) depending on how you hold the pencil. This can cause dramatic and unsightly variations in line thickness as you write or draw. The Kuru Toga eliminates this problem with the use of an ingenious lead rotation mechanism that continually rotates the pencil lead as you write. A spring-loaded clutch twists the lead incrementally every time you lift the pencil from the paper. This allows a uniform wearing of the lead to create a conical tip shape that provides a fine, consistent line. This Kuru Toga Advance features an updated "W Speed" mechanism, which rotates the lead twice as fast as standard Kuru Toga pencils so that the lead gets sharpened twice as quickly. Standard Kuru Toga pencils rotate the lead once every 40 strokes, while the Kuru Toga Advance rotates the lead once every 20 strokes. The Advance's mechanism also features metal parts for smoother, more reliable performance. The Advance also features a sliding lead sleeve (guide pipe) that protects the lead as you write. As you write and the lead gets shorter, the sleeve slides into the pencil, getting shorter along with the lead. This means that you can write continuously without clicking to extend more lead, all the way until the sleeve gets too short. The sleeve can be fully retracted when the pencil is not being used, protecting it from getting bent or poking a hole in your pocket or pencil case.