U.S. Acoustic Seismic Intrusion Detector

This is an air dropped acoustic seismic intrusion detector ( ACOUSID ) which reported its data by radio frequency. This style of detector was first used during the Battle of KHE in 1967 dropped by helicopters. It was also one of the systems used during operation igloo White which was a convert U.S. joint military electronic warfare operation conducted form late January 1968 to February 1973. This example is in very good condition.

Code: 65413