rOtring Isograph Technical Pen, 0.30 mm

Amazon

High precision pen with refillable ink reservoir for drawing The hard chrome-plated thin tip produces exquisite, detailed work The wear-resistant tip prevents dripping and blobbing Designed so that ink level is clearly visible, so you know when it's time to replace the ink Ideal for use on a variety of surfaces including line board, tracing paper and vellum drawing paper

Euroffice

Low odour, quick drying, permanent ink, water and rub-resistant. Colour band indicates ink colour. Chisel tip line width: 1.2-5mm