The instrument in invigilation is a mobile phone signal shield.
The shielding power of the mobile phone in the small space of the classroom is small, and the installation position is stipulated. The distance between the classroom corridor and the wall behind the podium is usually more than 2-3 meters, which has reduced the harm of electromagnetic radiation to human body to a safe range. In other words, when invigilating, just try to stay away from the shielding device.
All objects in nature always transfer heat to the outside world in the form of electromagnetic waves as long as the temperature is above absolute zero. This way of transmitting energy is called radiation.
Such as home TV, refrigerator, air conditioner, microwave oven, vacuum cleaner, office mobile phone, computer, copier, electronic instrument, medical equipment, etc.
Not all intensities of radiation will harm human beings. It is related to the length of time the instrument is turned on and personal physique.
Of course, you'd better put protective clothing on the baby.