working PSID detectors vintage military electonic surveilance system motion

Description

These are tested and are fully functioning. Some have the clip broken off with time. Please see photos and read description below for more details. This has an aircraft radio with the right frequency to opperate this device included. Very good overall condition but not perfect.  Included is 1995 Guns and Weapons magizine with article on this device. Everything is working, set and ready to use.  Batreries not included.
This comes in its original box.
NEW, unused Geophone-based Platoon Seismic Intrusion Detector set with 4 transmitters. Matched set with all the same frequency with transmitter codes 1,2,3,4. Each transmitter operates on 1 or 2 - 9 volt batteries. Operates well on one battery but use 2 batteries if set is to be in place for longer periods, such as 30 days. Set is packaged in the original issue canvas carrying bag. These are NEW units that have been tested to ensure functionality but they have never been used in the field. They are of vintage age, produced during the Vietnam era and are military surplus. Pin clips on these units are very brittle due to age and may be broken or break easily, but this does not affect functionality. Although this set is new and unused, with no apparent issues and has been tested before posting, it is considered sold in AS-IS condition and not returnable.A receiver is NOT included with this set, however a programmable police and fire scanner or several other types of radios can be used as a receiver.Uses: These transmitters are placed in perimeter locations where you want advance warning of the approach of a person, vehicle, or even animals (depending upon the sensitivity setting) into a protected area. The frequency of this set is 129.000 MHz.General information from other sources: Military issued TRC-3 Wireless seismic intrusion detectors offer the BEST edge for perimeter protection. Seismic probes detect minute earth vibrations and detect a person walking, a vehicle driving by or even LOW FLYING aircraft within a 20-30 yard circumference around each probe. Each probe also has its own sensitivity setting, you might want one probe more (or less) sensitive than the others. The detection is sent via the attached transmitter to the receiver. The intruder never knows they are detected until it's too late.Each sensor is connected to its own transmitter by an eight-foot cable. This allows the sensor itself to be buried or submerged. Each of the sensors can monitor footstep vibrations in an area 260 feet in diameter and movement of heavy vehicles to a much greater distance. Activated in seconds - even in total darkness - each sensor / transmitter is corrosion-resistant and ruggedized for reliable operation under severe conditions. Each transmitter also has a small "wipe" antenna that transmits the tone back to the receiver.Pulse tone coding allows monitoring all transmitters simultaneously on the same radio frequency. Similar to Morse Code, each transmitter emits a different number of tones when activated and matches the number of pulses embossed on the transmitter housing for swift, sure identification by touch - even in total darkness. Transmitters have built-in sensitivity controls and an on/off switch. The system can be used with any combination of one to four transmitters. Each transmitter has the number of "dots" that is transmitted. Example "4 dots" means that there would be four beeps broadcasted. (An occasion the number of beeps is not discernable on some units, but they are differentiated by tones)
working PSID detectors vintage military electonic surveilance system motion.... Condition is "New".