Object used and are in AoT(Signal Flare)

Signal Flare:

The Signal Flare is a common tools used in the Military by the Garrison and the Survey Corps. The signal flare has a variety of uses depending on the mission.

Uses:

While the Signal Flare has many uses, its main purpose is long distance communication. The Garrison uses it as a way to inform the higher-ranking officers how their mission is going while the Survey Corps uses it as a way to communicate (often in the presence of Titans) to the rest of the legion.

Ammo:

The ammo used depends on the mission at hand. The ammo the Garrison uses is the following:

• Green - Mission started.
• Red - Mission failed.
• Yellow - Mission successful.

The ammo the Survey Corps uses for the 57th expedition beyond the Walls is the following:

• Red - Titan spotted.
• Black - Deviant Type Titan spotted.
• Purple - An emergency of some kind.
• Blue - An order to retreat.
• Green - Change direction of the formation: Fired by the commander in one direction to indicate a change in the direction, and then repeated by the relay soldiers.
• Yellow - This lets everyone know that the mission has been terminated, be it successfully or failed.
• While leading the Female Titan through the Forest of Giant Trees, Levi used a special shell that emitted a high-pitched noise.