Concealment device

Concealment devices or diversion safes are used to hide things for the purpose of secrecy or security. They are made from an ordinary household object such as a book, a soda can, a candle, a can, or something as small as a coin. The idea is that such an inconspicuous object would not be expected to contain anything of worth.

Examples in espionage include dead drop spikes for transferring items to other people, and hollowed-out coins or hollowed out teeth for concealing something - such as microfilm or a suicide pill. Examples in smuggling include suitcases with false bottoms for hiding contraband.

During World War II MI9 was responsible for creating many concealment devices for "escape aids" to assist prisoners of war to escape.

Starting in the First World War and still continuing today, military personnel use ammunition casings to hide small amounts of critical information e.g. encryption/recognition codes or navigational grid references etc. The hiding place is very easy to prepare: the bullet is removed from the cartridge and the propellant powder poured away. A small piece of paper with writing on it can be stored inside. Given that ammunition can be found everywhere in a combat zone, it is very easy to hide or discard such items because they blend in easily. Similarly, if a soldier is captured, the enemy expects that soldiers will have ammunition in their pockets, so little attention is paid, beyond confiscating and discarding it.

Books are possibly the most common concealment devices in usage. They are easily made and can contain quite large objects. They are also very difficult for outsiders to spot but easy to recognize for those that are looking for a specific book on a shelf.

A new type, the hollow candle looks like a large scented candle but is mostly hollow. The bottom comes off and rolled papers or small objects can be placed and hidden inside. Some of the most clever of these contraptions looked like large, ordinary black candles with a felt base concealing the opening. To open them, two metal needles are poked through the felt at certain points and an electric current passed through, causing them to open.

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