Refrigerator temperature monitor with wireless digital display for freezer 1.Max/Min Temperature The Max/ Min temeprature data will update every 24h. Pls be attention that the product cannot hold the max/min temperature all the time. ^ 2.Alarm With audible alarm, you can set the maximum and minimum alarm value manually. It can ring when the temperature value reaches at the point of limit max or min alarm value that you pre-set.^ 3.Easy Use There are 6 function keys on the main unit and signal indicator on the transmitter, you just press the corresponding key to turn on/off the alarm, switch the Celsius or Fahrenheit. ^ 4.With integrated magnets, a hanging hole and a bracket at the back, you can put the main unit in refrigerator door, hang on the wall or stand on the table. ^ 5.Please install the new battery to make sure the accuracy.