BioEditExperimental Phase 2 Armor (ARC Armor, or simply Phase 2 ARC Armor) is an early version of Phase 2 Clone armor, which was originally worn by ARC Troopers to demostrate Phase 2 Armor capabilities.
The armor itself, is a combination of both Phase 1 and 2 armor, with a rugsack, or datapack similar to what Sandtroopers (Phase 3 Imperial Shocktroopers) wear. The datapack itself, is meant to be a reinforced comlink device, used to communicate with nearby troops, ships, and officers.
The armor consists of having a large pauldron, thick armor chest plate, skirt (kama), a datapack, modified versions of Phase 1 helmets with rangefinders, and thick knee armor.ARC Troopers, or Officers were the only Clones to wear this version of armor, and many well-known Clones; such as Fives, Colt, and Echo; wore the armor.
The datapack is actually what inspired the Empire to equip their squads of Imperial Shocktroopers for the Imperial Security; while the pack is practically like a portable radio device similar to what US Army soldiers used during World War 2.
Because of how unique the armor looks, most fans have had a high demand for Hasbro and LEGO to produce Experimental Phase 2 ARC Troopers in action figure and mini-figure form.