The Ein replacement core Stein has a structure that supports the core from the inside with a strong silica frame, achieving the highest level of strength. Therefore, it is hard to break. Furthermore, by balancing the contradictory elements of strength and density, it is possible to create strong and dark handwriting. Graphite, which is the main component of the core, has excellent adhesion to the surface of paper, is strong against hand and paper contact, and is resistant to abrasion. Therefore, the handwriting of the notebook is clear and perfect for making beautiful notes. A case that allows you to remove the core by turning the lid. Core diameter 0.5 mm. Core hardness B. 40 leads.