A Zeer pot is an evaporative cooler. In 90 degree weather you can see cooler temperatures in the 40′s. Basically it’s two clay pots separated by a layer of water infused sand, and a wet towel over the top. If the inside of the interior pot is glazed (water proof), seawater or other non-potable water can be used instead of fresh water. It doesn’t get much simpler than that.
A tomato that lasts 2 day on the counter can last 20 days in a Zeer pot.