The advanced power armor Mark II represents a significant upgrade over the older Mark I. It is composed entirely of lightweight ceramic composites, providing even more protection than the regular advanced power armor. Unlike the Mark I, the Mark II features a large profile, and more effective, segmented armor plates to achieve a superior degree of protection, with the hump replaced with pauldrons that evoke old world power armor designs, such as the T-45. The helmet assembly retains the insectoid eyepiece arrangement of the Mark I helmet, but the overall shape has been changed to an even more insect-like appearance, with a reduced vertical profile.

The suit was originally available in limited qualities. Following the destruction of the oil rig and the flight to the Capital Wasteland, the Enclave has designated the Mark II as its official service uniform and manufactured it en masse once it gained access to Raven Rock and Adams Air Force Base, eventually displacing the older, less protective Mark I suits entirely.

The Frozen-Devils are the main units on Portland during the events of the Frontier, their armor is specialized to resist the harsh winter & cold of the post-war city.