The war amulet, also known as a battle amulet, is a device in Jak 3 used by Spargus citizens as a safety beacon and proof of citizenship. The amulet is made of Precursor metal and consists of three parts; a circle-shaped center and two half moon-shaped parts that fit around the center. Jak receives a new part each time he proves himself worthy to Damas after fighting in arena battles.
The wastelanders use these when they are in some case of emergency, however when Jak used his in the palace ruins it did not appear to give any sign of activity when it was activated. It did turn out later on that the call was received however, as Damas came to their rescue.
Jak earned his first part in the "Earn 1st war amulet" mission and respectively the second in the "Earn 2nd war amulet" mission. The third was to be earned in the "Defeat marauders in arena" mission, which Jak failed to complete, however he redeemed himself and got the last piece after defending Spargus from a Dark Maker assault.