Susutake bamboo is known as smoked bamboo. Thats because in rural Japan, after long years of sitting above a slowly burning stove, the bamboo darkens into a beautiful honey brown color - dark underneath, with a lighter brown facing upward. It also has a patinated, aged and antique appearance giving it unique appeal. Due to the long 'curing' process, the bamboo becomes very tough and stable.The surface is "sealed" and toned with urushi lacquer, with a process known as "fuki-urushi" in which raw urushi "ki-urushi" is rubbed into the surface, wiped off and dried for 24 hours, several times over. Every SUSUTAKE fountain pen is just that little bit different from the last due to the fact that the bamboo grain is different and each piece is wholly hand made. Also each pen feels and performs a little differently. The ends of the cap and the barrel pieces are made from ebonite.