The Kaweco Royal Blue M 6-pack of refills provides high-quality ink for classic, fluid, and erasable writing. This set includes 6 standard universal short cartridges with brilliant royal blue ink that flows perfectly and won't clog the nib feeder. Compatible with pocket-sized or traditional nib pens using the European standard, they are very practical for quick replacement. The brightness of royal blue is the preferred standard choice for school notebooks, personal correspondence, and everyday office tasks.