Shield Door

Shield Doors are Covenant made "doors" that are able to allow people and machines through while keeping plasma and gunfire out. They are similar in design to energy shields that the Jackals wear.

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

Now they are also featrued as forge items in the new hero map pack and they can be placed anywhere.