Make sure that the switch on the side of the cooler and warmer is turned off, then plug the power cord into the socket The cooler and warmer car fridge is energy saving and eco-friendly, semiconductor refrigeration system, non-pollution, long life, low noise and consumption A perfect item for family road trips or anyone who spends a lot of time driving and gets hungry and thirsty on the road Environmental protection without fluorine pollution ,small capacity,light weight,long service life Perfect for using in car or for picnics