Treat your work to an injection of colour with this single ballpoint refill by Boss. The refill is versatile and designed to fit all Boss ballpoint pens. The blue refill is perfect for signing official documents to show it is an original copy rather than a photocopy. The ink is instantly drying on your page to help eliminate smudging from your work. The medium rolling ball nib is ideal for those looking for a smooth and fluid line on the page.