From Halopedia, the Halo wiki
The drop wall is a piece of equipment similar in operation to the deployable cover and drop shield. When deployed, the drop wall projects a large energy shield which protects its user from enemy fire in combat, while still permitting the user to shoot through it.
The drop wall is a usable piece of equipment in Halo Infinite. It can be deployed in combat to provide the player with a temporary shelter from enemy gunfire, and is capable of stopping both gunfire and grenades. Additionally, the player is still able to shoot through the deployed drop wall, at their enemies. However, it degrades easily under damage, so the respite it provides is temporary.
List of appearances