Schneider&reg; Topball 850 Black 0.5 mm Rollerball Refills - 2/pk you are buying TWO Schneider Topball 850 black rollerball refills ink: black 0.5 mm line [Schneider defines as "medium"] universal rollerball refill; fits most rollerball pens bulk packaging; we are a USA supplier...buy with confidence Also available in a Four Color Pack [TB850-4ColorPack] as well as in an Assorted Color Ten Pack [850-Assorted]