Armor Ability

Armor Abilities are exclusive gameplay enhancements featured in Halo: Reach. It is a refined version of Halo 3's Equipment feature, where instead of being used once, each ability will be reusable, with a cooldown time between uses. It is unknown whether these may be picked up and traded, or earned and equipped like armor permutations.

Sprint
Sprint allows the player to lower their weapon and move at an increased speed for a certain length of time.

Active Camo
The Active Camo provides players the ability to have Active Camouflage for a period of time, similar to Thel 'Vadam's active camo from Halo 2. It, however, will not hide the user's presence and will be visible on nearby enemy's motion tracker on multiplayer mode. However, It will jam the enemy's radar similar to the Radar jammer in Halo 3. It will also deaden sound for the user.

Jet Pack
The Jet Pack ability allows players to maneuver in mid-air. It will be useful for evading splatters, grenades, and navigating maps.

Trivia

 * As revealed in the Multiplayer Trailer, there seems to be two additional armor abilities that grants the player Invincibility/Overshield and Dodge Roll, a forwards roll to evade danger. There also appears to be a third new armor ability that grants the player a Bubble Shield similar to the one seen in the original Halo 3 trailer.