This Sheaffer Ballpoint Pen Medium Refill Cartridge Black is perfect if you find yourself running low on ink in your Sheaffer ballpoint pen. This refill is made from metal to ensure its longevity and sturdiness.-The fefills are a perfect fit in all Sheaffer Ballpoint Pens.-The refill has a medium nib size.-The ink in this refill is a crisp black.-Refilling your pen is simple and easy.