This is a case of 20 pencil leads suitable for Uni Kuru Toga mechanical pencils. The lead has a special composition: a soft outer layer around a harder inner core. As a result, the lead can be easily shaped into a point, which is what Kuru Toga pencils are uniquely designed to do. The lead case comes in various colors, and the slim profile slips easily into your pencil case.
You can definitely see the difference between the lead grades of B and HB. The
lead holder for this is cylindrical and slim compared to the standard flat,
rectangular lead holders. It is more easily portable in pockets (but like all
things, be careful not to lose them such as it falling out when you least expect