Equipment

Overview
The philosophy of Equipment is simple: to add a variety to the combat during gameplay without unbalancing the game. Plus the different variety of equipment can benefit a player in different ways.

Halo: Combat Evolved
In Halo: Combat Evolved, the only Equipment available on demand was the Flashlight. You could pick up two types of bonus Equipment, the Active Camouflage and the Overshield. Both types of Equipment would only last a limited time before wearing off.

Halo 2
In Halo 2, the only available equipment was Master Chief's flashlight and The Arbiter's active camouflage (Though with a certain skull, Master Chief would gain camouflage as well). Although such equipment could not be collected or spent, they were always available for use (based on charge) being integrated into their respective armor.There were two types of power ups, Active Camouflage and Overshield. After awhile, the effect of the power ups would wear off.

Halo 3
In Halo 3, equipment items can be used by both attackers and defenders in both Multiplayer and Campaign, though the flashlight is retained for campaign. It is not entirely clear which faction, Human or Covenant, manufactures each piece of equipment, although the Covenant are main users of the equipment. This could imply that the Covenant manufacture most of the equipment used in the game.

In Halo 2
Campaign Only:
 * Flashlight
 * Active Camouflage

In Halo 3
Available in Campaign and Multiplayer:
 * Bubble Shield
 * Power Drain
 * Gravity Lift
 * Trip Mine
 * Regenerator
 * Active Camouflage
 * Overshield
 * Flare
 * Deployable Cover
 * Radar Jammer

Campaign Only:
 * Automated Turret
 * Cloaking
 * Invincibility

Custom Maps Only:
 * Custom Powerup

Trivia

 * In the January 2008 issue of EGM, in an interview with Brian Jarrard and Tyson Green, it was revealed that there was a piece of equipment cut from the final game known as The Vortex. It was said to be deployed the same as a Power Drain, but would instead create a mini black hole that would "suck" in any object within range, and diverting its course into the black hole, and away from your face. It was even able to affect nearby objects such as the Fusion Coil and even other players. The design was cut due to the fact that it was too "expensive" from a networking and performance standpoint.
 * The Radar Jammer, Flare, and Deployable Cover are no longer usable in Matchmaking; the Deployable Cover due to the ability to assist players in jumping to places they should not be, the Flare because they seemed cheap and unbalanced, and the Radar Jammer for sheer lack of player acceptance.
 * If you are an Elite and have a Radar Jammer, Power Drainer, Trip Mine, or a Flare you can look straight down, hit X, and then A an instant later, if you do it right, then you will jump off the equipment, making it useful for getting to high places.
 * In the Forge, you can manipulate the game so that you can spawn equipment continuously. Press the X button (default configuration) on the item, pressing X again and changing the Run-Time Minimum to the same number as the Number on Map while cause the item to spawn immediately after being picked up.
 * In the new 2009 Halo 3 Action Figures wave, there are equipments included, and it should be noted that they all can be moved in some way as if they were activated; for example, the Radar Jammer included with the Olive Security-permutation Spartan has two handles on it that the Spartan can hold as if to be able to deploy the equipment, and these are connected to disk-like parts of the Radar Jammer that extend during use and, when deployed jams everyone's (including your) radar showing the are multiple enemies nearby even though there might be none.So thats it.