Temperature Range: This wireless indoor/outdoor refrigerator thermometer has an indoor temperature range of -10°C to 60°C (14°F to 140°F) and an outdoor temperature range of -40°C to 60°C (-40°F to 140°F). (Batteries not included) Audible Alarm: The wireless refrigerator thermometer's alarm console provides audible and visual alarms when the temperature exceeds the preset minimum and maximum alarm limits. After setting the alarm temperature, a short press of the alarm button will display the \"Alarm\" icon and activate the alarm function by default. Multiple Installation Options: Note: Do not place this product in hot, humid, dusty, or corrosive environments to avoid damage to its electronic components. Easy to Use: The main unit has six function buttons, and the transmitter has a signal indicator light. Just press the corresponding button to turn on/off the alarm, switch between Celsius and Fahrenheit, and clear the max/min values. Note: If the sensor does not connect, please try the following: 1. The normal connection distance between the main unit and the transmitter is up to 100 meters. 2. Reinstall the batteries in the main unit and the transmitter. The transmitter needs to wait 3 minutes to receive the signal from the main unit. 3. Press and hold the ALARM and CLR buttons simultaneously for 3 seconds to force the unit into long-term connection mode. 4. Replace batteries or try again.