Indoor temperature detection range -10°C-60°C (32°F-122°F); Outdoor temperature detection range -40°-60° (-40°F-140°F); Transmission range: 100 meters/328 ft., no obstructions. This wireless refrigerator thermometer has an audible alarm and can manually set the maximum/minimum alarm value. It ring when the temperature value reaches your preset maximum/minimum alarm value. But when the temperature alarm is just turned on, no matter whether the temperature reaches the alarm's temperature range, it not alarm and ring after 10 minutes. This digital refrigerator and freezer thermometer comes with remote sensors, which can display indoor temperature and 1 sets of outdoor temperatures at the same time. Even if the sensor is placed outside or in a warehouse, you can record the temperature without leaving your home. The maximum/minimum temperature data is updated every 24 hours, but there is no function to record the maximum/minimum temperature data, and the maximum/minimum temperature cannot