Take a look at what makes an Engel Deep Blue Performance Cooler the number one rated cooler in the country. Roto-molded of seamless polyethylene, it's tough enough to stand up to a hungry grizzly bear. (In fact, it's an approved bear-resistant container.) A full 2" of dense polyurethane foam is injected top, bottom and sides to provide 8-10 days of cold-keeping capability. But this is just the start.