Product review (5 stars): Keeps cool for hours
Works like a charm here in southern Arizona.  Only used cooling mode. You must precool the unit before putting into a hot car. Once it is precooled it stays cooled. If I do not have time to precool then I throw in bags of frozen peas or make a big ice bag. I have had it stay cool for several hours. One of the plugs broke after 8 months and they send me a new replacement. I rely on this cooler to keep the food fresh while shopping, especially in the hot Arizona summers.