These fine roller refills feature a rotating ball of tungsten-carbide (a material as tough as diamond) housed in a stainless-steel tip. Installing the ball in the tip is a high-precision operation. This is the only way to ensure that writing will stay clean and smooth to the very last drop of ink – never catching, never blotting.
Each Caran d'Ache cartridge is individually tested for unimpeded ink flow and are suitable for all Caran d'Ache roller/fiber-tipped pens. Made in Switzerland.