This incredibly precise technical pen is suitable for professional technical and detailed drawing. The ink in these pens is water resistance, and archival quality in terms of permanence. It is also highly pigmented, giving a beautifully opaque black line. ‘Isograph’ are refilled from a bottle. These pens are available with a choice of 11 different nib widths (ranging from 0.1mm to 1mm) to suit your requirements. - Acid free: Yes - Brand: Rotring - Main material: Plastic - Permanence: Archival quality permanence - Pen type: Technical pen - Water resistant: Yes - Ink colour: Black - Nib width: 0.1mm, 0.13mm, 0.18mm, 0.2mm, 0.3mm, 0.35mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 1mm