A: 4 times writing length, direct-injection ink storage, capacity upgrade, 4 overhead neutral pens
B: Japanese MIKUNI ink, bright and full
C: 0.5mm spring bullet, not easy to leak ink
D: It is not easy to fly white and break ink, and the writing is smoother
E: The pen is quick to dry, it is not easy to smash when it meets water, and the writing is durable and not easy to fade