Weight: 1 lb.
Estimated Value (Sane Cost Guide): 100 gp
DMG Value:
101 gp - 500 gp
This portable arcane instrument points in the direction of the last portal it passed through while it and the portal are on the same plane of existence. If that portal no longer exists, the needle becomes static until the compass passes through a new portal.
Source: Planescape: Adventures in the Multiverse (Sigil and the Outlands) p13
