From Halopedia, the Halo wiki
The helmet includes a Buffalo A-29 comm suite, which works flawlessly with the ad-hoc and anarchic telecommunication networks found in many colonies. Some models of the helmet have the "Mark of the Breaker" skull emblazoned on the visor.
Developed by the Naphtali Contractor Corporation, the Orbital variant was tested and was the first to survive the Buffalo Breaker Yards testing site. This granted some models of the helmet a distinct skull emblem, known as the "Mark of the Breaker", on the visor.
The suit is a modified variant following the same production lines as the EVA-class Mjolnir, though it was developed specifically for orbital and suborbital combat, where conditions similar to space often converge with harsh atmosphere and gravity-borne challenges.
It was also field-tested during the battles in the skyhooks and space elevators on Earth and Luna during the Battle of Earth. This test was a success, leading to the Orbital-class armor's adoption by Spartan-IVs.
Patrolling Spartans equipped with ORBITAL-class Mjolnir armor are a common sight near Earth's orbital tethers and military space stations.
Available skins: Aeon (AEON) and Swift (SWFT)
Halo 5: Guardians
Available skins: Aphelion, Equinox, and Perihelion
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 skins
Halo 5: Guardians skins
List of appearances