Alwan Isograph Technical Pen, 0.1 mm Nib

A technical pen draws a line of exactly one width, in any direction, with no variation from pressure or angle — which is the entire point of it. The nib is a fine steel tube with a weighted wire inside that keeps the channel clear, and the pen refills from a bottle instead of being thrown away when it runs dry.

Technical pens are for drawing that has to be measured rather than felt: architectural work, plans, orthographic projection, ink hatching, and stencil lettering. Hold it close to vertical — a tubular nib laid over at an angle starves and skips. And the single habit that decides how long the pen lasts is capping it the moment you stop: ink drying inside the tube is what blocks a technical pen, and clearing a blocked nib is slow, fiddly work.

0.1 mm is the finest in the range: hatching, texture, and the detail layer that sits on top of everything else. It is also the most delicate nib and the first to block, so it is the one that most rewards the capping habit.

• Tubular steel nib — one constant line width in every direction
• Refillable from a bottle of technical drawing ink
• Hold near vertical; a tilted nib starves and skips
• Cap it the moment you stop — dried ink inside the tube is what blocks it