These black Staedtler Pigment Liners are truly versatile tools.
Long metal tip and softer writing action makes them easy to use with rulers and templates for technical and architectural drawing.
Lightfast, quick-drying, smear-free and indelible.
Since they are waterproof, you can also use them with watercolours or other water-soluble media without bleeding.
And if you leave the cap off, you can leave them for 18 hours before they dry out.