This thermostat is very simple to use. Just press the up arrow to set the temperature (in 0.1 degree increments). There is a flame indicator on the screen that shows when the heater is operating. The unit has an 18 inch remote sensor that is placed inside the incubator. The white thermostat case is then mounted on the outside of the incubator. Finally you can measure the temperature right next to your eggs, not the air at the top of the incubator. This can be set to read in Celsius or Fahrenheit Comes preset to 99.5 (this means that if you lose power the thermostat will come back on set to 99.5) - Preset to 37.5 in Celsius mode Thermostat set point can be adjusted to any temperature between 41 - 113 degrees Fahrenheit Digital readout displays temperature to the tenth of a degree (examples: 98.0, 99.5) If the temperature goes over 99.9, it reads: 00.1, 00.2, 00.3, etc Designed specifically for incubators, great for small incubators AND cabinet incubators (can switch heating elements up to 225 Watts) Remote Temperature Sensor (18 inches long) Select your voltage above in the drop down box (110V AC OR 220/240V AC). 110V AC is for North America and a small number of other countries. 220/240V AC is for most places outside of North America. Temperature Switching Differential = 0.2 degrees Fahrenheit. This means if the thermostat is set to 99.5 the thermostat will turn the heat on when the thermostat sensor reads below 99.3 and turn off when the sensor reads above 99.7. Calibration Enabled. This means that you can calibrate the thermostat to a specific temperature. (calibrate in 0.1 degree increments up to +/- 5 degrees) Wiring and operation instructions included. Key lock feature allows you to set the temperature and lock the keys so it cannot be changed without unlocking the keys.