Portable gravity lift

Were you looking for the more permanent Gravity Lift?

The Portable Gravity Lift is a piece of Covenant deployable field equipment.

Operation
Once deployed, the Portable Gravity Lift unfolds and projects a bluish-purple stream of gas and energy that propels personnel into the air. The stream is powerful enough to lift vehicles, such as the Mongoose, as well as other moderately heavy objects.

Covenant troops presumably use the lift to reach high ledges in a similar manner as using conventional ladders.

Strategies
One tactic that has been used is deploying a Gravity Lift and then sending a Power Drain or grenade up to the enemy above; this requires a deal of luck as well, not to mention either needing:
 * When placed near a wall, a player can use this device to jump on or over it.
 * Doorways can also be blocked with it, by sticking enemy players on the ceiling, or if in Forge place it horizontally so it pushes the player away. This is especially useful when playing Juggernaut as it can push the Juggernaut into an area, essentially holding the Juggernaut there.
 * Both a Portable Gravity Lift and Power Drain close together.
 * Two teammates close together and able to coordinate this tactic, which is often difficult to manage.
 * The Gravity Lift can also be used when you are about to be splattered by a vehicle by deploying the Grav Lift in front of the vehicle. The driver will not be able to avoid it and the vehicle will be sent flying. It is important to crouch immediately after deploying the Portable Gravity Lift because some light vehicles, such as the Warthog and the Brute Prowler, can still clip you in the head as they fly over you.
 * You can drop it on top of an active Bubble Shield which will cause it to rise above your opponent, leaving him unprotected.
 * You can use it to great effect to flip over light vehicles, or reduce the handling of larger ones. Any Ghost or Mongoose moving over one at high speed is likely to flip over when landing, and will prove to be a pain for even Scorpions and Wraiths. It is theoretically possible to use one with momentum to get a Splatter you would not otherwise have.

Forge

 * When in Forge mode, you can place an active Gravity Lift that does not require pickup for activation, so that in game it will already be active.
 * If you put one Gravity Lift over another in a room with a roof so that the gravitational forces face each other, they will counter each other and the player will be unaffected or will float but still be able to steer through.
 * In Forge, you can place a Gravity Lift on top of a weapon holder. If done correctly the gravitational force from the holder will turn the Gravity Lift sideways, so instead of lifting you up vertically, it will push you horizontally. This can be used to keep players from entering doorways or certain areas.
 * If you set the minimum respawn to the maximum respawn, and keep throwing a gravity lift in the same place, it will 'Jump' over the other gravity lift, eventually finding its very own 'place' to rest.
 * Using the above trick, if you throw them in an upward direction with permanent gravity lifts surrounding you, the portable ones will go up, and 'jump' around in seemingly random positions; from below, it looks like glowing-blue sentinels are attacking you.

Disadvantages

 * Usage of the Gravity Lift inside (with a roof above) can trap the player, as they cannot escape the lift's force, pressing them against the ceiling. However, this can also be used as a defense.
 * Also, portable or not, the Gravity Lift can still be destroyed by conventional weaponry and will self-destruct after 30 seconds. An active Gravity Lift will not survive a fall from a great height.
 * Once trapped, it is easier to throw a grenade (frags work best) into the lift and it will shoot up and kill or injure the trapped player. This has to be done properly though, as it can also fly back out of the lift and detonate somewhere else, making it a clever trick to do, but an easy suicide.
 * Gravity Lifts will not effect heavy vehicles such as the Scorpion, Wraith, and Elephant, but just barely have an effect on Brute vehicles like the Chopper and Brute Prowler. This may be because the Brute vehicles already use repulsion (or similar) technology in their vehicles, making them difficult to flip, and would only need to use a little more energy to counter the Lift.

Appearances
The Portable Gravity Lift was seen in the H3 ViDoc while a group of players were attacking High Ground. To the untrained eye one would suppose that a player just grenade jumped, but there was a pad on the floor that was radiating a blue light similar to the Man Cannon. It is another piece of equipment similar to the Bubble Shield, Power Drainer, Trip Mine, and Radar Jammer.

Trivia

 * The Gravity Lift is used in obtaining the Cowbell Skull, on "The Ark" level of Halo 3. You have to position the Gravity Lift in an exact place on the floor and jump to get it.
 * When deployed in front of a rapidly approaching vehicle, the approaching vehicle will fly upwards (above your head) except for Ghosts. This tactic also works with enemies in both Single Player and Multiplayer, and is very effective against charging Brutes.
 * The Portable Gravity Lift is available for use in multiplayer on the maps High Ground, Sandtrap, Rat's Nest, Ghost Town, Foundry, and Last Resort.
 * The Portable Gravity Lift is the only piece of equipment that can be placed in Forge in its deployed stage.
 * If you drop a Portable Grav-Lift while riding a fixed one (made in Forge) or another portable one you will be launched twice as high, but the lift you drop will then start spinning.
 * In a CTF game, if you throw a Gravity Lift at the flag, the flag will float into the air, making it easier to capture in some situations.
 * The Portable Gravity Lift can be destroyed by two grenades detonated in close proximity.

List of appearances

 * Halo 3