During the Cold War, spies from both the East and West utilized specially modified coins to covertly transport messages, microfilms, poisons, etc. This new and improved version still applies and can fit a micro-SC card or other similarly sized device (only in the half dollar - quarter can fit smaller devices)

Machined from actual coins to create a secret interior compartment, these are nearly undetectable and indistinguishable from regular coins to the untrained eye. They can be handled normally without any chance of an accidental opening. An opening device is supplied with each covert coin, without which it's next to impossible to open up the coin.