The previous Corporate Cavalry unit for the Siege had three-section arms. The purpose of this unit is to carry a heavy weapon usually requiring a stationary gun post. Its primary application is as a mobile, anti-infantry support weapon.
This version has slaved robotic arms like Masamune Shirow’s landmates, but set closer to the wearer’s shoulders and rather than copying the wearer’s arm movements, it assists in carrying and aiming – this is a semi-automated system that learns from its user.
If you compare their surfaces, there are more synthetic muscles and fiber-based armour on this one.
The change came from combining the sketches of the hardsuit snipers with the research that went into the previous CAV unit.