the special lead diameter of only 0.9 mm is ideal for fine and precise marking, without sharpening, for automatic lead advance, for a long lasting lead holding power, made of extremely dimensionally stable special plastic, with extra-strong clip, for durable use, with effective dust and wetness protection: Push button as umbrella cap and sealing ring on the barrel, its integrated large eraser makes markings correctable in a flash, equipped with 5 graphite leads in HB, sustainable as refillable with different refills, high-tech push mechanism for automatic lead advance in stainless steel tube, barrel with roll stop