"QMD / X3" is a 940Nm Infrared grenade device emitting radiation that is invisible to the human eye, a monitor monitor and a CCTV camera.
When the grenade is activated, it emits radiation intermittently, a kind of stroboscopic flash blinding the night surveillance cameras within a radius of 40m.
The camera shoots the exposed grenade in real time, the monitor has an almost white screen corresponding to infrared radiation, when a visitor passes between the camera and the grenade, his image appears on the monitor.