An item that shows you where is the specific point on a map. You can set the target point by typing in coordinates, or pointing at place with your crosshair and pressing `place` button while `sneaking`. Once point is set, you "own" the compass. You can give it to other people, but only you will be able to change the settings.

To `unset` the compass (or un-own it), open the settings and remove the coordinates (leaving an empty field for "position"), save it, and now compass is (almost) like new.