Depending on where it is to be sold, your Thermofocus (01500A3 model) leaves the factory preset with the display off when in stand-by mode (“Energy Savings”) or display on and showing the room temperature for 4 hours before shutting off (“Peak Performance”) , These settings can be modified as follows: When the thermometer is in stand-by mode, press and hold the “mem” button (or “face” button in the older models); after about 8 seconds, the visualization on the display changes, showing the settings in sequence: °C, °F, AXILLA, ORAL, RECTAL, “home” on, “home” off. When the desired setting appears, release the button (“home “ on means that the display will show the ambient temperature for 4 hours before shutting off, “home” off means that it will shut down immediately after the 20 second interval after the last reading.