The formula is secret the pencil is world-famous. Staedtler success story began over 180 years ago, with manufacturing pencils. To this day, first-class, sustainably sourced materials and manufacturing processes outstanding and consistent product quality. Staedtler Mars Lumograph is available in up to 20 degrees of hardness for writing, drawing and sketching on paper, canvas, matte drafting film and more. Super bonded lead resists breaking while sharpening and drawing, both. Plus it wears evenly and erases cleanly. This pencil pack is not only an ideal creative companion for drawing and sketching purposes, but drafters, engineers and even school age kids will benefit from the finest German manufacturing processes. Whether its scientific or creative endeavors, in the home, office or classroom, Staedtler helps bring ideas to life.