Gel rollerball refill rollerball refill · Use for product: suitable for all Waterman rollerballs · Type of ink cartridge: rollerball refill · Type of writing fluid: ink, lightfast, waterproof · Refill design: metal tip, fine, black. A Waterman rollerball pen combines traditional ink with ultimate writing comfort. The unique experience of evenly silky and effortless gliding is completed by three intense ink colours and a perfect line width. Press freely and show how passionate you like to write.