Active camouflage

The Active Camouflage power-up is light-bending energy which is stored in the same way as the Covenant Overshield. When the user breaks the active camouflage container, the energy envelops the wearer and bends light around the skin, armor, or shielding, conforming to it's user's form, rendering him almost invisible. This effect wears off as the energy dissipates.

When any projectiles pass through this shielding, it is temporarily deactivated causing the user to become visible. It should be noted that this is speculation based on field reports, and has not been proven because no one has yet captured an intact device.

The technology can be utilized on human armor systems, such as the MJOLNIR armor, but the UNSC has only developed a rough equivalent, the Camouflage Cloak.

Some Elites have active camouflage generators, as do some Grunts. The Arbiter has old armor with an old active camouflage generator that needs to recharge after using the camouflage for too long.

Combat Usage
The Camouflage covers the entire body. The coverage does not extend to the entirety of the user's equipment. Lights like on the Plasma Pistol and Plasma Rifle can be seen, as can the Energy Sword, giving away the user's position. Also, if close enough the Characters outline is seen faintly and it looks like a moving silhouettes. Yet it's hard to see the outline and the seemingly "ghost" from a far angle. Even on a scope Like the Sniper Rifle or Battle Rifle it can be hard to see the opponent.

In Halo 2, it is noted that the Arbiter's armor, while possessing an in-built active camouflage generator, is not permanent until turned off, unlike the more modern generators used by SpecOps Elites. There is a circle on the player's HUD that shows the amount of time left for both the usage of the active camouflage and the recharging sequence. The Master Chief can gain this ability with the Envy Skull.

Unlike in Halo: Combat Evolved where one could attack without breaking active camouflage permanently, in Halo 2 usage of a weapon causes active camouflage to deactivate until it is recharged and can be used again.

'''Notes:

In Halo:Combat Evolved active camouflage does not hide you from the Flood Infection Form, they still know where you are.

By changing the graphics card settings on Halo PC, active camouflage users appear as a big purple figure and are very visible.'''

In Halo 3
It appears the Active Camo will no longer be kept inside a triangular box. It seem to be a glowing "ball" in the Halo 3 Beta and appeared on High Ground, Last Resort, and Snowbound.