American dollar coin used for concealment

Concealment devices, as the term suggests, are used to hide things for the purpose of secrecy.

Examples in espionage include dead drop spikes for transferring items to other people, and hollowed-out coins or teeth for concealing suicide pills.

Examples in smuggling include suitcases with false bottoms for hiding contraband.

The picture at right shows a hollow container, fashioned to look like an Eisenhower dollar, which is still used today to hide and send messages or film without being detected. Because it resembles ordinary pocket change, it is virtually undetectable as a concealment device.