Bought 1 of these 55qt coolers about a year ago. It is used everyday and lives in the back of my pickup truck. Not sure of the cause but the walls of the cooler became warped it no longer held a good airtight seal. I sent an email to the warranty dept at Lifetime and discribed the problem. A few back and forth questions and they are sending me a new cooler. What a great company. I may go buy the new 77 qt cooler now.