The unusual, insect-like design features a pair of polarized eyepieces in place of the usual vision slit, providing superior battlefield awareness. Perhaps the most noticeable change was a completely new helmet assembly. The resulting space savings allowed for reducing the armor's profile without compromising protection. While the T-51 power armor relied on a lightweight poly-laminate composite shell for protection, the advanced model uses lightweight metal alloys as basis, reinforced with ceramic castings at key points.

The X-01 advanced powered infantry combat armor is designed for a single human operator, provided with the comfort and protection of a next-generation suit of armor. This allowed the Enclave a limited production of the suits. The schematics for an earlier version of the armor was saved by the Enclave just before the bombs fell, with the organization keeping copies in the archives of their Poseidon and Whitesprings facilities. Further development was halted, due to the outbreak of the Great War. While the suit served as a successful proof of concept of using a strontium-90 based plating over the armor, this improvement was not adopted into the armor's schematics before the onset of the Great War. A single suit of X-01 MK V was given to the Nuka-Cola Corporation, as part of their Project Cobalt. While the first test models were issued to Presidential bodyguards, the X-01 was never deployed in larger numbers. However, although the suit was technically functional by late 2077, it was burdened with numerous issues that precluded widespread use in the field. It represented a radically new approach to designing powered armor, eschewing traditional design philosophies that defined the T series, and was a high-profile research project meant to supersede previous power armor models. The development of the X-01 began shortly before the Great War.

X01 power armor mods