The Cross Black Pen Refill, in a pack of 6 units, is compatible with Cross permanent ink pens, guaranteeing smooth and consistent writing throughout their lifespan. Having several refills available is essential for those who use the pen regularly, avoiding running out of ink at important times for work or study. The quality of Cross ink ensures a uniform, flawless stroke, maintaining the writing performance that users of the brand are accustomed to. It is an economical and sustainable way to extend the life of the pen instead of replacing it.