Automaton Gear
The Automaton Gear is an item of God of War: Ghost of Sparta.
In the game, Kratos comes across big and metallic enemies known as Automatons, which use a metallic gear as their weapon of choice. As the gear is connected to their hand, Automatons can used their gears as a chain weapon which is useful for range-attacks.
The Gear also has a second function as a key. Kratos acquires a gear everytime he defeats an Automaton and puts it at incomplete mechanisms to open doors or activate certain structures.
Like the Automatons themselves, the Gears were created by Lanaeus to serve as pieces of big structures around the game, and specially in Atlantis.