1.The measuring surface is about 2cm below the infrared aiming point. 2.For best accuracy, the distance between the thermometer and object of measurement should approximately be 14.17inches (36cm). Simple Operation - Point and Click! This Etekcity non-contact IR temperature gun is easy to operate. It turns on and begins reading the temperature with one press of the trigger. Clear text displays the measured temperature in either Celsius or Fahrenheit. A laser light aids in aiming, and can be turned on or off. In addition, the readout display features a backlight which can be turned on if needed. 12: 1 High distance spot ratio! This means you may measure the temp of a smaller area at the same distance compared to other 8: 1 thermometers; thus the readings are much more accurate! Reliable Product.