Wu-Xing War Compass
From Warhammer - The Old World - Lexicanum
Wu-Xing War Compasss are powerful magical war machines of Grand Cathay. 
Smaller versions of the great Compass engraved into the floor of the Celestial Court which hangs high above Wei-jin. Imbued with the power of the Heavens, a Wu-Xing War Compass can be used to manipulate the Elemental Winds.
Expensive to build and maintain, each of them can also be used as a deadly weapon of war, with meteors and lightning storms summoned in its wake. Some Cathayan Astromancers use them as mounts in battle.