This small round case is no more than a round controller! Also called "Snitch", this object was adopted in the 60's by the surveillance teams.
At that time we had numbered keys in secure boxes on the sites to be monitored.
When passing through various predefined points on his patrol rounds, the agent manually inserted the numbered keys into the back of the round controller. The stamped waypoints are recorded and plotted on a paper tape located inside the mechanism.
60 years later, the round controllers have changed immensely! They now provide a digital transmission of data and make it possible to track, in real or deferred time, the rounds carried out by the security officers.