Perfect for taking customer's temperatures as they walk into a store, checking friend's temperature before they come inside your home, or even taking your own or your family's temperature on a regular basis. It will help make sure their body is operating near or at normal temperature (98.6 F). Please note that you shouldn't solely or primarily use this to diagnose disease, and high temperatures should be checked with a secondary source like a medical-grade thermometer. Press the button and find out someone's surface heat within seconds, hold down that same button to switch from degrees Fahrenheit to degrees Celsius. Temperature displays on a large backlit screen. Comes packaged in a hanging box, takes 2AAA batteries, and batteries are not included.