Check the listing for details. 1set Wireless Freezer Thermometer 2 Remote Sensors Alarm Digital Display Clock. Color: Silver, Condition: New. Listed at 21.68 USD. Package Included:1 x Host2 x Sensor1 x USer Manual Features:- Alarm FunctionWhen the temperature of the test exceeds the maximum or minimum temperature set by the thermometer, the thermometer will sound an alarm to remind you to adjust the temperature.- Temperature Trend DisplayTrend indication of 3 groups of temperature: for real time test, if the deviation between the test temperature and current temperature is more than 1 degree, the trend indication of temperature shows the sign of UP; if the indication between the test temperature and current temperature is less than 1 degree, the trend indication of temperature shows the sign of DOWN; if the deviation between the test temperature and current temperature is in the scope 1 degree in 1 hour, the trend indication of temperature shows the sign of PARALLEL. Description:1.Easy to read LCD screen displays the current indoor outdoor temperature.When insufficient electricity,there are will be shown on the LCD screen.2.With a temperature trend indicator arrow and daily high and low information.3.Display stands upright for tabletop use or is wall-mountable.4.Includes 24 hours high and low records for temperature.5.The display console displays temperature,minimum and maximum temperature, which can be reset manually. Specifications:1.433 Mhz transmission frequency2.Update Rate: 10 seconds3.Transmission range up to 328 ft(range maybe shorter based on interference present)4.Indoor Temperature range:0℃~50℃（32 ℉ ~ 122℉）5.Outdoor Temperature range:-40℃~60℃（-40 ℉ ~ 140℉）6. Power Supply: AAA Battery(Not included) Note:1. Do not install the reverse battery2. Do not put the receiver near metal3. Avoid transmitter directly in the rain4. High-quality batteries for the use of main unit and transmitter better5. The sensor search mode allows you to re-sync sensors without removing and re-inserting batteries. How to Install the Sensor:The thermometer's digital display is magnet-mountable on a fridge,or use the integrated keyhole for wall mounting. The wireless thermometer sensors are equipped with a spring-loaded clips with a Plastic grip to securely attached to the edge of a shelf.