Shield door

One of the Shield Doors on Snowbound.

Shield Doors are Covenant and Forerunner made "doors" that are able to allow people and machines through while repelling plasma and gunfire. They are similar in design to the Bubble Shields, with the only difference being the color. Also, the Shield Door is similar to the Shield Barrier (seen on Tsavo Highway).

There are several in past Halo games and they appear in Halo 3 on the multiplayer maps Epitaph and Snowbound.

Now they are also featured as forge items in the new Heroic, Legendary Map Pack and Mythic map pack and they can be placed in almost any door as well as anywhere else the Forge user desires.

If one stands exactly in the shield door's energy field, doing a melee or shooting in any direction will be negated by the shield. However, the player is still vulnerable from attacks from either side. This also works with the Bubble Shield. By "overloading" a map with shield doors (Using excessive trip mines to cause the map to lose control of the maps graphical and geometrical assets), the shield doors on a map will disappear.

Trivia

• Despite the fact that shield doors protect from projectiles, plasma and vehicles, explosions can still affect players and objects on the other side of them. A perfect example of this is the underground shield on Snowbound, where the nearby power coils can be detonated to instantly kill players standing on the other side. It is unknown if this is a glitch or Bungie meant to do this.