Active camouflage

The Active Camouflage power-up is light-bending energy which is stored in a triangular glass case. It is similar to the way a Covenant Overshield functions. 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.

Function
The Camouflage covers the entire body. The coverage does not extend to the entirety of the user's equipment. Human weapons won't give away the user's location as much as Covenant weapons do. 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 character's outline is seen faintly and 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.

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. 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.

When playing as the Arbiter, using any attack will cause the active camouflage to deactivate, and the player must wait for it to recharge before using it again.

Use in Campaign
If the active camouflage is active during campaign, your are completely invisible to the AI enemies unless you fire your weapon which will deactivate the camouflage for a short amount of time. Though the chances you get to use the Active Camouflage in campaign aren't very often other than when you are playing as the Arbiter in Halo 2 and the two levels in Halo: Combat Evolved, Truth and Reconciliation, Silent Cartographer, and Assault on the Control Room.

Active Camouflage and Shielding
An odd discrepancy is present in the difference between Halo: Combat Evolved and Halo 2 active camouflage. In Halo, Stealth Elites using active camouflage had no shielding whatsoever; furthermore, Elites were the only Covenant to possess it. However, in the last level, a Flood Elite was seen with an Active Camouflage. In Halo 2 active camouflage was seen in use by both Elites and Grunts (only in Arbiter level and part of Regret).

In "A Day At the Beach," an Elite Minor is seen engaging his own active camouflage at the expense of his shields (though when the camouflage seems to be shorted out by the Plasma grenade explosion his shields are reactivated).

It can be conjectured from this evidence that perhaps all Elite armor has active camouflage systems installed, but in all but the highest echelons of Elite rankings the power drain deactivates the shield in favor of the camouflage. Only Ultra Elites and Special Operations Elites seem to have enough power in their armor to run both systems at the same time.

In Halo 3
The Active Camo is no longer contained inside a pyramid. It appears as a large, glowing sphere in Halo 3 multiplayer. Unlike past Halo games, active camo is not found in campaign. In campaign, Active Camouflage is replaced by the Cloaking equipment, which functions in the same way as active camouflage once used. Melee attacks, shooting, throwing grenades, and using equipment will negate the effect of the powerup.

The quality of camouflage in custom games may be set to three different settings :
 * Poor Camo: The player has camouflage that might fool a Grunt.
 * Good Camo: The player has camouflage that will fool an attentive Elite.
 * Invisible: The player is perfectly invisible when not shooting.

Trivia

 * In Halo: Combat Evolved, active camouflage does not tend to hide you from the Flood Infection Form as well, they still know where you are.
 * By changing the graphics card settings on Halo PC, active camouflage users appear as a big, single-color figure and are very visible.'''
 * Active camouflage covers the Energy Sword in Halo 3, unlike in the previous games.