From Halopedia, the Halo wiki
The helmet has a Torque-node component used to distract nearby predators, the base of the node detects levels of gravity-trough scaturiency. The helmet also features extended awareness conduits (ALK-03) which heightens mobility around senior operatives and moving-equipment personnel. The visor has lodged-tracking component 793-VF for improved survivability and maintenance. The chest has 90-RZ java-fuel monitoring software which evaluates current sustainability levels.[Note 1]
Fotus was created by 343 Industries, by merging loose Forerunner technology and base Mjolnir architecture. It was originally forged at the RTC Facility before being transported to the Willows Complex for durability and survivability testing. At a later point it was tested at 434 Combat Readiness Lab where it was tested extensively in Kirkland's overcast and frigid nine-month winter season.[Note 1]
Before full production of the armor could start, engineers required that it meet COUGAR-class safety protocols in an effort to protect it against feral branches of wildlife. These protocols were met and Fotus armor sets were deployed.[Note 1]
A skin of this armor was part of the Forerunner Hybrid Kit, which is a group of equipment using classified Forerunner technology from Requiem, it was developed for highly experienced Spartan-IV by the Office of Naval Intelligence.
Fotus armor has proven invaluable in Seattle's corporate shadow-wars.
Unlock: This armor was a pre-order bonus with the Halo 4 Limited Edition Xbox 360 console.
Halo 5: Guardians
Available skins: Chillrose and Synchronize
In Halo 5: Guardians due to the "Body" having a predefined customisation this armor set permanently has the following parts from Halo 4:
Halo 4 skin
Halo 5: Guardians skins
List of appearances