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: 100 meters/328 ft., no obstructions. This wireless refrigerator thermometer features an audible alarm with manual setting for maximum and minimum alarm values. The alarm will sound when the temperature reaches the preset threshold. Upon initial activation of the alarm function, no alarm will occur immediately regardless of current temperature; the system will begin monitoring after a 10-minute delay. This digital refrigerator and freezer thermometer includes remote sensors that simultaneously display indoor temperature and one set of outdoor temperature readings. Even when the sensor is placed outdoors or in a separate location such as a warehouse, you can monitor temperature conditions without leaving your home. Maximum and minimum temperature data are updated every 24 hours; however, this device does not continuously store historical temperature records, and extreme values may not be permanently retained. Equipped with hanging holes and a stand on the back, the main unit can be mounted on magnetic surfaces such as refrigerator doors or microwaves, or placed upright on a table. Versatile installation options make it easy to use. Power supply: 2 x AAA batteries and 4 x AA batteries (not included) Color: White + Black Material: Plastic Model: 1 to 2 Package Contents: 1 x Thermometer 2 x Transmitter 1 x English Manual Only the items listed above are included; other accessories are not included. Note: Lighting effects and display settings may cause slight variations between the color shown in the image and the actual product. Measurement error allowance: +/- 1-3 cm.