How Does A Forehead Thermometer Work ?

They measure infrared energy radiating from the forehead or temple area. I have used one
and they are fairly accurate. More so than the ear probe and little or no difference between
the hospital mouth kind or the drug store digital kind. The druggist said not to use on someone with heat stress because it doesn't measure inner body high core temps as well.

You just put the thermometer on the forehead and run across them lift up and read the temperature.