The formula is secret – the pencil is world-famous!- It was with pencils that STAEDTLER’s success story began.- To this very day, first-class materials and manufacturing processes guarantee outstanding and unbeatable product quality.- STAEDTLER Mars Lumograph is available in up to 16 degrees – for writing, drawing and sketching on paper and matt drafting film.- The super-bonded lead wears evenly and is easy to erase and sharpen.