Orb of Relative Depth
Wondrous Item, common
While holding this orb, you can use an action to determine whether you are located above or below up to 3 preset preset locations. The first location is the location where the orb was created – this location cannot be changed. The second location can be set by the orb’s user by spending 1 minute touching the orb to a surface of that location. The third location is always the previous location where the orb was used. The orb has no memory, and once the second and third locations are changed, they cannot be brought back without returning to the location and attuning the orb again. The orb is not a tracking device, it measures only relavite depth, so if the depth of a stored location changes, the orb will still hold its original depth.