These small tracking devices had a piece shaped like a rose and a clear medallion with the cardinal directions clearly marked.
The rose was attached to any solid, nonliving surface, where it would send out a signal for up to 100 miles (161 km). The medallion could trace the signal like a compass. A tiny arrow would appear on the medallion when traveling in the right direction. A simple command word was need to detach the rose. Dispel magic, or similar effects made the compass rose inoperable for one day but did not allow someone to remove the rose.