The Forest Camo Balaclava is a piece of clothing that is worn on a player's head. It provides decent protection from various types of damage. The Forest Camo Balaclava, as of Devblog 73, is a fairly new item that seems like a work-in-progress.
This is a skin for the Improvised Balaclava item. You will be able to apply this skin when you craft the item in game.