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 feet) without obstructions. This wireless refrigerator thermometer features an ble alarm with manual setting for maximum and minimum temperature thresholds. The alarm will activate when the measured temperature reaches the preset limits. Upon initial power-up, the alarm will not trigger immediately regardless of temperature; it becomes active after 10 minutes. The digital display shows indoor temperature and one set of outdoor temperature simultaneously via remote sensors. Monitor temperature conditions remotely even when the sensor is placed outside or in a separate area such as a warehouse. Maximum and minimum temperature values are updated every 24 hours; however, this device does not continuously store historical temperature data or maintain max/min records indefinitely. Designed with hanging holes and a stand on the back for flexible placement. Can be mounted on magnetic surfaces like refrigerator doors or microwaves, hung on a wall, or placed upright on a flat surface. Easy to install and operate. Power supply requires 2 x AAA batteries and 4 x AA batteries (batteries not included). Color: white + black. Material: plastic. Package includes: 1 x thermometer, 2 x transmitters, 1 x user manual. Additional items not included. Note: Lighting and screen display settings may cause slight variations in color between the image and actual product. Measurement error allowance is +/- 1-3 cm.