It represented a radical, new approach to designing powered armor, eschewing traditional armor design philosophies, but was never deployed in larger quantities until the 23rd century. The first test batch of the armor, designated X-01 Mk I, was developed for presidential bodyguards, and served as the baseline for the remnants of the United States military, who developed it into a power armor tailored for the post-War wasteland.

The development of the first suit of advanced power armor, designated X-01, began shortly before the Great War.