The hard poly box has been in two iterations I believe. It is a very snug fit, so close that some may not allow the pack to accept the box within the sewing tolerances. CCS has made a pack slightly larger in perimeter and height to better meet the needs of fitting the current BWJ poly box. BWJ has a few of these newer larger packs on hand and will be picking up more tomorrow.
As far as additional insulation people have added an additional 1/2" thick closed cell foam pad around the body on the inside as well as matching the size of the bottom and top lids out of closed cell foam. Others have done a layer of Reflectix® and duct taped them to form the body tube size with a dusted taped on bottom with a floating lid that is just above the cold food allowing the dried food that needs no cooling to be outside of the cool zone.
Others that have a small amount of food needing cooling use a Reflectix® bag and fold over the top to keep the cool in a very limited area.
Dry ice mid summer has lasted for over 5 days in the stock foam lined food pack.
I drop in an RTIC 30 soft sided cooler with ice packs in the bottom of my Deluxe Food Pack. It fits with plenty of room, and every year our steaks on evening 2 are frozen solid. Probably works too good. Our eggs froze last year!
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