Ensure your Waterman rollerball pen is always ready to effortlessly produce precise lines. The rollerball refill is filled with intensely dark black ink for dramatic yet clear marks. Refilling is easy with the Waterman rollerball pen refill. To replace, simply unscrew your pen, remove the empty cartridge and reassemble the body. The black ink and fine nib combine to create detailed lines that flawlessly mark on most surfaces.