jj, já ten název nevěděl a taky jsem googlil
XM-2 Personnel Detector « Forgotten Weapons
http://www.forgottenweapons.com/accessories/xm-2-personnel-detector/
People sniffer - Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/People_sniffer
a vypráskaná legrace s ním asi byla
The XM-2 personnel detector manpack, also known as the E63 manpack personnel detector,[3] was the first version of the people sniffer employed by the Army. The XM-2 featured a backpack mounted sensor with an air intake tube on the end of a rifle.
The XM-2 was problematic in often detecting the soldier carrying it rather than the enemy. The device also made a distinct sound, easily detectable by the enemy.