ITT Corporation, a defense and information systems company, wanted to send invitations to a press dinner held the night before the Defence and Security Equipment International tradeshow in London. The invitations needed to fit the DSEi top secret, high-security theme and stand out from all the invitations that the writers in the defense industry receive.

Upon opening the case, recipients found an envelope imprinted with "Top Secret Mission For:" and then seemingly empty brackets, along with a pen.

Inside the envelope the card read, "Critically useful covert assembly planned. ITT Corporation is hosting a concentration of press professionals preceding DSEi 2009 for some off-grid relaxing." However, again, important information seemed to be missing from the date, time and location brackets.

The pen, positioned with the invitation inside the case, was tagged with, "Electromagnetic ionizing radiation device."

"The targeted purpose of this ultraviolet imaging pen is to illuminate printed messages invisible to the human eye. With a wavelength approaching 400 nanometers, this hand-held industrial laser will reveal your top-secret mission."

Under the ultraviolet light from the enclosed pen, the sender's logo, ITT Corporation, was revealed.

As was an image of the tower bridge in London.

The private dinner for the press attending the DSEi tradeshow was to be held in the upper walkway of the tower bridge. The date, time and location were clear when read under the UV light.

Nearly 100 percent of the invitees attended the dinner. All commented that the invitation had really caught their eye and piqued their imaginations.