Feather file for nut
This file helps to shape or reshape the string slots of the nut. Shaping the slots correctly is important in order to let them hold the string properly and at the right height for best playability. It is made in Japanese Steel, resistant and precise. The feather file is essential for shaping the slots of the thinner strings while the other slots can be shaped with larger files or other tools that might be easier to "improvise".