Rollerball Gel Ink Pens Smooth Writing

0.5mm tungsten carbide roller ball is similar as diamond, let your writing fluent and smooth, make the pen durable and long lifetime.
Stable neutral ink makes your writing smooth and durable, quick drying, no ink skipping and leaking, won’t permeate and overspread the paper.
There is a transparent window to observe the capacity of ink, it is convenient to prepare a backup before the ink use up.