"Just aim the unit, press the button on top and either hold it to take a continuous temperature reading or release the button, which will hold the temperature on the display for 15 seconds. It measures from -27 to 230°F (-33 to 110°C), under the back cover there is a switch which can be pressed to display the temperature in either Celsius or Fahrenheit. The ''distance to spot ratio'' is 1:1, which means at 1 inch away from the surface, the unit will measure a spot that is 1 inch in diameter. At 1 foot, it measures a spot that is 1 foot in diameter, so the unit should be held as closely as possible to the surface being measured.What's Included: two batteries, and built-in pocket clip."