A handy tool to keep track of the temperature of your perishables. An essential accessory for every 4WD, RV or camper trailer with a fridge/freezer on those long drives or camping. Easy to install. This Thermometer has a range of up to 165ft transmission. It updates every 60 seconds and is powered by AAA batteries which are also included. Internal temperature measurement ranges from -40? to 140?F with ?1?C accuracy, whilst ambient temperature measures from 32?F to 140?F. (Note, Thermometer only reads in Celsius)