Phase I version
ARC Trooper armor was lighter and offered more protection than standard clone trooper armor. The armor could be fitted with specialized attachments, such as a jetpack, rocket dart launchers, miniature flamethrowers, and a rangefinder. The ARC Trooper Fordo also had a taser that could be shot from his gauntlet, which he used against Durge at the Battle of Muunilinst. Null-class and Alpha-class ARC Troopers had a HUD or heads up display built into their helmets. These allowed their wearers to control the functions of the armor, display information, highlight enemies, show tactical information and distance to the target during the battle. The HUD was controlled by eye movement. Also, the Null-class and Alpha-class armor had the ability to regulate the temperature in the armor and had a holoprojector in the glove.
ARC trooper armor was usually worn with a blast dampening kama and rank signifying pauldron. An exception was ARC trooper Alpha-98 "Nate" later "Jangotat". ARC trooper armor also included additional pouches and holders for grenades, land mines, blaster ammunition, med kits, and even extra rations. Prudii Skirata wore a specialized ARC trooper armor with stealth coating that could not be detected by droids.
Recruited ARC-troopers Phase II version
Sometime during the war, a prototype of Phase II version ARC Trooper armor was developed and issued on Kamino. The helmets were hybrids between the two versions, with the Phase II helmet's design sporting a shorter version of the Phase I helmet's antenna crest on top. Likewise, the pauldrons had extra chestplates, and a life support pack was usually worn on the back. ARC Trooper Colt and at least three others were known to have worn such armor during a Confederate assault on Kamino. Later, troopers CT-21-0408 and CT-27-5555 would also wear this armor. During 21 BBY, ARC trooper helmets later were changed to have the shape of a standard Phase II clone trooper helmet, as evidenced by CT-27-5555 when he fought in the Battle of Umbara.