Handheld Thermal Gun Scanner thermometers use a lens to focus the infrared energy from an object onto a sensor that measures it, typically a thermopile. The sensor absorbs infrared radiation and converts it to an electrical signal, with more intense radiation creating a stronger signal. Benefit: Being a non-contact object, there is a lesser chance of passing on the infection or germs from one person to another. Unlike a contact thermometer, you do not have to wash these thermometers after every measurement making these devices suitable even for bulk or professional temperature monitoring. If you have a baby at home, you can measure the body temperature easily with an infrared thermometer even when your kid is sleeping.