Skybuilders' Leather

Skybuilders' Leather is miscellany used in the Ishgardian Restoration.

Source
Skybuilders' Leather can be crafted by leatherworkers as a level 20 recipe with the following materials:
 * x6
 * x1
 * x4
 * x2

Uses
Skybuilders' Leather is exchanged for in custom deliveries to Potkin in The Firmament.