Mobile box in the package to match the military. In the middle is a small logbook and pencil. If you find a box to try to move it to another mailbox or in some other place.
Any transfer of a box, please log on the website geokrety.org.
GK3EEB Eldridge

The mailbox name is derived from the name of Eldridge USS Eldridge who participated in the Philadelphia Experiment which allegedly was to be held October 28, 1943 year.
The experiment was to prove the existence and investigate the properties of unipolar magnetic field. The theory on which the experiment was conducted was allegedly developed by Albert Einstein, in preparation for the experiment, but Einstein had taken part as John von Neumann, and Nikola Tesla. Unipolar action of the magnetic field would lead to the USS Eldridge was undetectable to radar.
According to the ship after a few minutes became completely invisible. Part of the crew died, accompanied by various hours of the disease, many mental illnesses reached and some claimed that they moved in time.