This digital refrigerator and freezer thermometer comes with remote sensors that display indoor temperature and one outdoor temperature reading at the same time. Even if the sensor is placed outside or in a warehouse, you can record the temperature without leaving home. - Indoor temperature detection range -10°C to 60°C (32°F to 122°F); Outdoor temperature detection range -40°C to 60°C (-40°F to 140°F); Transmission range up to 100 meters/328 ft, with no obstructions. - This wireless thermometer has an audible alarm and allows manual setting of maximum and minimum alarm values. It will ring when a reading reaches your preset threshold. When the temperature alarm is just turned on, it will not alarm immediately and may ring after 10 minutes. - The maximum/minimum temperature data is updated every 24 hours, but there is no function to record the maximum/minimum data, and the maximum/minimum values cannot always be maintained. Use scenarios - Home use: monitor fridge and freezer temps while the outdoor sensor sits on a porch, balcony, or in a garage. - Small business or warehouse: track temperatures in a walk-in cooler or beverage cooler from an office or other room. - Seasonal storage or transit: keep an eye on temps in a storage unit or transport environment to protect perishable items.