Kuretake Bimoji pens are traditional Japanese brushes in modern marker form.
The Usuzumi version features a light gray water-based ink in a bristle-type brush tip. A great tool for both brush lettering and illustrations.
The new "Cambio" series features a continuous ink flow system with a solid barrel that doesn't require squeezing to release ink. Plus, when the ink runs out, the barrel cartridges are replaceable!