This unit has 2 temperature sensors. 1 inbuilt inside the unit and another sensor on a 3 met wire. Use the remote wire sensor to monitor fridges or freezers. Inbuilt alarms that can tell you that the temp limits are exceeded. Inbuilt Memory so that you can see what the temperature got up to and down to during the weekend or overnight. Wide range of -50 C up to +70C. With magnetic and velcro mounting. The remote sensor has a sticky mount, suction cap and screw down mount inc.