Staedtler Mars Professional Refill 716 (0.35mm)" /> 0.35mm Staedtler Mars Professional Drafting / Technical Pen Refill 716 Light-fast and permmanent - conforms to ISO 14145-2:1998 Black pigmented ink is water-based, fast-drying and acid-free Smudge-proof, resists bleeding Refill for Staedtler Mars Professional 712