The Feverscan Thermometer Test Strip is an easy and safe way to test for a high fever. Simply place the black side against a dry, unobstructed forehead for 15 seconds. The black boxes change color with heat and are marked with Celsius and Fahrenheit measurements. Wipe the reusable test strip down with a dry cloth after use and store it in its included polybag out of direct sunlight between uses. Includes instructions.