Everything about this pen, from its solid construction to its carefully-formulated ink, ensures a wonderful writing experience. The sturdy tip does not bend or break, even with heavy-handed use. The pigment-based ink flows smoothly and is waterproof, fade-resistant, and feather-resistant. Much of this great performance is due to the special viscous properties of the ink. As the ink passes through the pen tip during writing, the viscosity drops to provide smooth ink flow. But immediately after it hits the paper, the ink returns to its viscous state to prevent feathering. You are left with beautiful clean lines that you can enjoy for a long time!