### Comment:
https://en.wikipedia.org/wiki/Radar_detector#Radar_detector_detectors 
  
 https://en.wikipedia.org/wiki/Radar_detector_detector 
  


### REPLY:
&gt;...many early 'stealth' radar *detectors* were equipped with a radar-*detector-detector-detector* circuit, which shuts down the main radar receiver when the *detector-detector*'s signal is sensed, thus preventing *detection*...

### END.