Maxi Hb Graphite Pencils, Ideal For Industrial Use. 3.5 Mm √Ò Lead. Ergonomic Triangular Shape. The Hb Graduation Is A Medium Graphite Hardness, Recommended For Writing And Drawing. The Lead Offers A Uniform Line And Is Resistant To Breakage, Thanks To The Lps (Lead Protection System) System That Protects The Lead Thanks To Its Adhesion With The Wood. Wood From Sustainable Plantations.